# Redirect loop detected

**URL:** <https://community.letsencrypt.org/t/redirect-loop-detected/218510>\
**Category:** Help\
**Created:** [May 16, 2024, 10:17am UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510 "2024-05-16T10:17:30Z")\
**Posts on this page:** 13\
**Page:** 1

<div class="post-metadata">

**Author:** ![juimdpp](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/juimdpp/32/80015_2.png) [@juimdpp](https://community.letsencrypt.org/u/juimdpp)\
**Post date:** [May 16, 2024, 10:17am UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/1 "2024-05-16T10:17:30Z")

</div>

Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. [https://crt.sh/?q=example.com](https://crt.sh/?q=example.com)), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.

My domain is: `https://band.snu.ac.kr`

I ran this command: `certbot certonly --webroot -w /opt/mrsnu.github.io/ -d band.snu.ac.kr -v`

It produced this output:

```nohighlight
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator webroot, Installer None
Certificate is due for renewal, auto-renewing...
Renewing an existing certificate for band.snu.ac.kr
Performing the following challenges:
http-01 challenge for band.snu.ac.kr
Using the webroot path /opt/mrsnu.github.io for all unmatched domains.
Waiting for verification...
Challenge failed for domain band.snu.ac.kr
http-01 challenge for band.snu.ac.kr

Certbot failed to authenticate some domains (authenticator: webroot). The Certificate Authority reported these problems:
  Domain: band.snu.ac.kr
  Type: connection
  Detail: 147.46.15.17: Fetching http://band.snu.ac.kr/.well-known/acme-challenge/NJF3mw7CMde2oYCTus_ki57ux9sbXmjwQvmOjlUcJfE: Redirect loop detected

Hint: The Certificate Authority failed to download the temporary challenge files created by Certbot. Ensure that the listed domains serve their content from the provided --webroot-path/-w and that files created there can be downloaded from the internet.

Cleaning up challenges
Some challenges have failed.
Ask for help or search for solutions at https://community.letsencrypt.org. See the logfile /var/log/letsencrypt/letsencrypt.log or re-run Certbot with -v for more details.

```

My web server is (include version): nginx/1.18.0 (Ubuntu)

The operating system my web server runs on is (include version): Ubuntu 20.04.6 LTS

My hosting provider, if applicable, is:

I can login to a root shell on my machine (yes or no, or I don't know): Yes

I'm using a control panel to manage my site (no, or provide the name and version of the control panel): No

The version of my client is (e.g. output of `certbot --version` or `certbot-auto --version` if you're using Certbot): certbot 2.10.0

Additionally, I get

 ![image](https://global.discourse-cdn.com/letsencrypt/original/3X/0/4/04ae03846e8b7ac18c60c88e0386f8715a61b889.png)

---

<div class="post-metadata">

**Author:** ![Bruce5051](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/bruce5051/32/76576_2.png) [@Bruce5051](https://community.letsencrypt.org/u/Bruce5051)\
**Post date:** [May 16, 2024, 4:28pm UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/2 "2024-05-16T16:28:17Z")

</div>

Hello @juimdpp, welcome to the Let's Encrypt community. 🙂

Please show the output of `sudo nginx -T` ; that is a Capital **T**

Presently I see this [https://letsdebug.net/band.snu.ac.kr/1960368](https://letsdebug.net/band.snu.ac.kr/1960368)

 ![image](https://global.discourse-cdn.com/letsencrypt/original/3X/b/7/b7c846d8fd49607a0744ac40ad76b2a9edc2d381.png)

---

<div class="post-metadata">

**Author:** ![juimdpp](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/juimdpp/32/80015_2.png) [@juimdpp](https://community.letsencrypt.org/u/juimdpp)\
**Post date:** [May 17, 2024, 12:19am UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/3 "2024-05-17T00:19:16Z")

</div>

That's weird... When I tried yesterday, it ran without any problem. Here's the output for `sudo nginx -T`:

```nohighlight
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
# configuration file /etc/nginx/nginx.conf:
user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
        worker_connections 768;
        # multi_accept on;
}

http {

        ##
        # Basic Settings
        ##

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 2048;
        # server_tokens off;

        # server_names_hash_bucket_size 64;
        # server_name_in_redirect off;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        ##
        # SSL Settings
        ##

        #ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
        #ssl_prefer_server_ciphers on;

        ##
        # Logging Settings
        ##

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

        ##
        # Gzip Settings
        ##

        gzip on;

        # gzip_vary on;
        # gzip_proxied any;
        # gzip_comp_level 6;
        # gzip_buffers 16 8k;
        # gzip_http_version 1.1;
        # gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

        ##
        # Virtual Host Configs
        ##

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;
}

#mail {
# # See sample authentication script at:
# # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
# # auth_http localhost/auth.php;
# # pop3_capabilities "TOP" "USER";
# # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
# server {
# listen localhost:110;
# protocol pop3;
# proxy on;
# }
#
# server {
# listen localhost:143;
# protocol imap;
# proxy on;
# }
#}

# configuration file /etc/nginx/modules-enabled/50-mod-http-image-filter.conf:
load_module modules/ngx_http_image_filter_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-http-xslt-filter.conf:
load_module modules/ngx_http_xslt_filter_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-mail.conf:
load_module modules/ngx_mail_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-stream.conf:
load_module modules/ngx_stream_module.so;

# configuration file /etc/nginx/mime.types:

types {
    text/html html htm shtml;
    text/css css;
    text/xml xml;
    image/gif gif;
    image/jpeg jpeg jpg;
    application/javascript js;
    application/atom+xml atom;
    application/rss+xml rss;

    text/mathml mml;
    text/plain txt;
    text/vnd.sun.j2me.app-descriptor jad;
    text/vnd.wap.wml wml;
    text/x-component htc;

    image/png png;
    image/tiff tif tiff;
    image/vnd.wap.wbmp wbmp;
    image/x-icon ico;
    image/x-jng jng;
    image/x-ms-bmp bmp;
    image/svg+xml svg svgz;
    image/webp webp;

    application/font-woff woff;
    application/java-archive jar war ear;
    application/json json;
    application/mac-binhex40 hqx;
    application/msword doc;
    application/pdf pdf;
    application/postscript ps eps ai;
    application/rtf rtf;
    application/vnd.apple.mpegurl m3u8;
    application/vnd.ms-excel xls;
    application/vnd.ms-fontobject eot;
    application/vnd.ms-powerpoint ppt;
    application/vnd.wap.wmlc wmlc;
    application/vnd.google-earth.kml+xml kml;
    application/vnd.google-earth.kmz kmz;
    application/x-7z-compressed 7z;
    application/x-cocoa cco;
    application/x-java-archive-diff jardiff;
    application/x-java-jnlp-file jnlp;
    application/x-makeself run;
    application/x-perl pl pm;
    application/x-pilot prc pdb;
    application/x-rar-compressed rar;
    application/x-redhat-package-manager rpm;
    application/x-sea sea;
    application/x-shockwave-flash swf;
    application/x-stuffit sit;
    application/x-tcl tcl tk;
    application/x-x509-ca-cert der pem crt;
    application/x-xpinstall xpi;
    application/xhtml+xml xhtml;
    application/xspf+xml xspf;
    application/zip zip;

    application/octet-stream bin exe dll;
    application/octet-stream deb;
    application/octet-stream dmg;
    application/octet-stream iso img;
    application/octet-stream msi msp msm;

    application/vnd.openxmlformats-officedocument.wordprocessingml.document docx;
    application/vnd.openxmlformats-officedocument.spreadsheetml.sheet xlsx;
    application/vnd.openxmlformats-officedocument.presentationml.presentation pptx;

    audio/midi mid midi kar;
    audio/mpeg mp3;
    audio/ogg ogg;
    audio/x-m4a m4a;
    audio/x-realaudio ra;

    video/3gpp 3gpp 3gp;
    video/mp2t ts;
    video/mp4 mp4;
    video/mpeg mpeg mpg;
    video/quicktime mov;
    video/webm webm;
    video/x-flv flv;
    video/x-m4v m4v;
    video/x-mng mng;
    video/x-ms-asf asx asf;
    video/x-ms-wmv wmv;
    video/x-msvideo avi;
}

# configuration file /etc/nginx/sites-enabled/band_website_https.conf:
server {
    listen 443 ssl http2;
    listen [::]:443 ssl;
    server_name band.snu.ac.kr www.band.snu.ac.kr;

    ssl_certificate /etc/letsencrypt/live/band.snu.ac.kr/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/band.snu.ac.kr/privkey.pem;

    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_prefer_server_ciphers on;
    ssl_ciphers "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384";

    # Specify the root directory and index files
    root /opt/mrsnu.github.io;
    index index.html index.htm;

    #if (!-f "${request_filename}index.html") {
    # rewrite ^/(.*)/$ /$1 permanent;
    #}

    #if ($request_uri ~* "/index.html") {
    # rewrite (?i)^(.*)index\.html$ $1 permanent;
    #}

    #if ($request_uri ~* ".html") {
    # rewrite (?i)^(.*)/(.*)\.html $1/$2 permanent;
    #}

    location / {
        try_files $uri.html $uri $uri/ /index.html;
    }

    location ~ /.well-known/acme-challenge/ {
        allow all;
        root /opt/mrsnu.github.io;
        try_files $uri =404;
        break;
    }

    # Redirect server error pages to the static page /50x.html
    error_page 500 502 503 504 /50x.html;
    location = /50x.html {
        root /usr/share/nginx/html;
    }
}

server {
    listen 80;
    listen [::]:80;
    server_name band.snu.ac.kr www.band.snu.ac.kr;

 # location / {
# return 301 https://$server_name$request_uri;
    #}

    location /.well-known/acme-challenge/ {
        allow all;
        root /opt/mrsnu.github.io;
        try_files $uri =404;
        break;
    }

    location / {
        return 301 https://$server_name$request_uri;
    }

}

# configuration file /etc/nginx/sites-enabled/hcs_nginx.conf:
# /etc/nginx/site-avaliable/hcs_nginx.conf

# the upstream component nginx needs to connect to
upstream django {
    server unix:///home/firewall/fwmanager/hcs.sock; # for a file socket
}

# configuration of the server
server {
    # the port your site will be served on
    listen 8000 ssl;
    root /home/firewall/fwmanager;
    # the domain name it will serve for
    server_name hcs.snu.ac.kr; # substitute your machine's IP address or FQDN
    charset utf-8;

    error_page 497 https://$host:8000$request_uri;

    ssl_certificate /etc/letsencrypt/live/hcs.snu.ac.kr/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/hcs.snu.ac.kr/privkey.pem;

    # max upload size
    client_max_body_size 75M; # adjust to taste

    location /static {
        alias /home/firewall/fwmanager/static; # your Django project's static files - amend as required
    }

    # Finally, send all non-media requests to the Django server.
    location / {
        uwsgi_pass django; # for a file socket
        include /home/firewall/fwmanager/uwsgi_params; # the uwsgi_params file you installed
    }
}

# configuration file /home/firewall/fwmanager/uwsgi_params:
uwsgi_param QUERY_STRING $query_string;
uwsgi_param REQUEST_METHOD $request_method;
uwsgi_param CONTENT_TYPE $content_type;
uwsgi_param CONTENT_LENGTH $content_length;

uwsgi_param REQUEST_URI $request_uri;
uwsgi_param PATH_INFO $document_uri;
uwsgi_param DOCUMENT_ROOT $document_root;
uwsgi_param SERVER_PROTOCOL $server_protocol;
uwsgi_param REQUEST_SCHEME $scheme;
uwsgi_param HTTPS $https if_not_empty;

uwsgi_param REMOTE_ADDR $remote_addr;
uwsgi_param REMOTE_PORT $remote_port;
uwsgi_param SERVER_PORT $server_port;
uwsgi_param SERVER_NAME $server_name;
# configuration file /etc/nginx/sites-enabled/hcs_website_https.conf:
server {
    listen 443 ssl http2;
    #listen [::]:443 ssl http2;
    server_name hcs.snu.ac.kr www.hcs.snu.ac.kr;

    ssl_certificate /etc/letsencrypt/live/hcs.snu.ac.kr/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/hcs.snu.ac.kr/privkey.pem;

    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_prefer_server_ciphers on;
    ssl_ciphers "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384";

    # Specify the root directory and index files
    root /opt/labsite/_site;
    index index.html index.htm;

# if (!-f "${request_filename}index.html") {
# rewrite ^/(.*)/$ /$1 permanent;
# }

# if ($request_uri ~* "/index.html") {
# rewrite (?i)^(.*)index\.html$ $1 permanent;
# }

# if ($request_uri ~* ".html") {
# rewrite (?i)^(.*)/(.*)\.html $1/$2 permanent;
# }

    location ^~ /.well-known/acme-challenge/ {
        allow all;
        root /opt/labsite/_site;
        try_files $uri =404;
        break;
    }

    location / {
        try_files $uri.html $uri $uri/ /index.html;
    }

    # Redirect server error pages to the static page /50x.html
    error_page 500 502 503 504 /50x.html;
    location = /50x.html {
        root /usr/share/nginx/html;
    }
}

server {
    listen 80;
# listen [::]:80;
    server_name hcs.snu.ac.kr www.hcs.snu.ac.kr;

   location / {
        return 301 https://$server_name$request_uri;
    }

   location ^~ /.well-known/acme-challenge/ {
        allow all;
        root /opt/labsite/_site;
        try_files $uri =404;
        break;
   }
}

```

---

<div class="post-metadata">

**Author:** ![Bruce5051](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/bruce5051/32/76576_2.png) [@Bruce5051](https://community.letsencrypt.org/u/Bruce5051)\
**Post date:** [May 17, 2024, 2:33am UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/4 "2024-05-17T02:33:25Z")

</div>

@juimdpp,

Demonstrating the redirect loop.

You can see it with Let's Debug here: [https://letsdebug.net/band.snu.ac.kr/1961042?debug=y](https://letsdebug.net/band.snu.ac.kr/1961042?debug=y)

```nohighlight
IssueFromLetsEncrypt
ERROR
A test authorization for band.snu.ac.kr to the Let's Encrypt staging service has revealed issues that may prevent any certificate for this domain being issued.
147.46.15.17: Fetching http://band.snu.ac.kr/.well-known/acme-challenge/ZWJC1MyXHAs24c5OKWx0ASSVxWR0GYvX9bwFzlxIPe8: Redirect loop detected

```

```nohighlight
HTTPCheck
DEBUG
Requests made to the domain
Request to: band.snu.ac.kr/147.46.15.17, Result: [Address=147.46.15.17,Address Type=IPv4,Server=nginx/1.18.0 (Ubuntu),HTTP Status=302,Number of Redirects=2,Final HTTP Status=404], Issue:
Trace:
@0ms: Making a request to http://band.snu.ac.kr/.well-known/acme-challenge/letsdebug-test (using initial IP 147.46.15.17)
@0ms: Dialing 147.46.15.17
@661ms: Server response: HTTP 302 Found
@661ms: Received redirect to http://band.snu.ac.kr/00867224609/.well-known/acme-challenge/letsdebug-test
@661ms: Dialing 147.46.15.17
@1332ms: Server response: HTTP 302 Found
@1332ms: Received redirect to http://band.snu.ac.kr/.well-known/acme-challenge/letsdebug-test
@1332ms: Dialing 147.46.15.17
@2030ms: Server response: HTTP 404 Not Found

```

And here with `curl`

```nohighlight
>curl -i http://band.snu.ac.kr/.well-known/acme-challenge/sometestfile
HTTP/1.0 302 Found
Location: http://band.snu.ac.kr/002770519539/.well-known/acme-challenge/sometestfile
Connection: close
Content-Type: text/html; charset=iso-8859-1

```

The above redirects `http://band.snu.ac.kr/.well-known/acme-challenge/sometestfile`  
to `http://band.snu.ac.kr/002770519539/.well-known/acme-challenge/sometestfile`

```nohighlight
>curl -i http://band.snu.ac.kr/002770519539/.well-known/acme-challenge/sometestfile
HTTP/1.0 302 Found
Location: http://band.snu.ac.kr/.well-known/acme-challenge/sometestfile
Connection: close
Content-Type: text/html; charset=iso-8859-1

```

The above redirects `http://band.snu.ac.kr/002770519539/.well-known/acme-challenge/sometestfile`  
to `http://band.snu.ac.kr/.well-known/acme-challenge/sometestfile`

And thus the redirect loop.

---

<div class="post-metadata">

**Author:** ![juimdpp](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/juimdpp/32/80015_2.png) [@juimdpp](https://community.letsencrypt.org/u/juimdpp)\
**Post date:** [May 17, 2024, 6:51am UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/5 "2024-05-17T06:51:14Z")

</div>

Thank you so much for checking! It's really weird, because when I checked myself (with curl), I found that it works...  
I get the following:

```nohighlight
$ curl -i http://band.snu.ac.kr/.well-known/acme-challenge/sometestfile
HTTP/1.1 404 Not Found
Server: nginx/1.18.0 (Ubuntu)
Date: Fri, 17 May 2024 03:06:28 GMT
Content-Type: text/html
Content-Length: 162
Connection: keep-alive

<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.18.0 (Ubuntu)</center>
</body>
</html>
(base)
hscor@DESKTOP-QGVRU2G MINGW64 ~
$ curl -i http://band.snu.ac.kr/.well-known/acme-challenge/file.txt
HTTP/1.1 200 OK
Server: nginx/1.18.0 (Ubuntu)
Date: Fri, 17 May 2024 06:47:34 GMT
Content-Type: text/plain
Content-Length: 7
Last-Modified: Thu, 16 May 2024 10:11:30 GMT
Connection: keep-alive
ETag: "6645dbd2-7"
Accept-Ranges: bytes

Hello!
(base)

```

Also, would you recommend me some steps that I could follow to make this work? It would be really helpful!

---

<div class="post-metadata">

**Author:** ![MikeMcQ](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/mikemcq/32/52772_2.png) [@MikeMcQ](https://community.letsencrypt.org/u/MikeMcQ)\
**Post date:** [May 17, 2024, 1:47pm UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/6 "2024-05-17T13:47:37Z")

</div>

What firewalls or other network devices do you have between your nginx server and the public internet? Because it looks to me like some security device or software is doing an initial set of redirects. Possibly for any new IP address making a request.

See below series from my own test server

```nohighlight
# Notice redirect with series of numbers after the domain name
curl -i http://band.snu.ac.kr/.well-known/acme-challenge/Test404
HTTP/1.0 302 Found
Location: http://band.snu.ac.kr/001246640706/.well-known/acme-challenge/Test404
Connection: close
Content-Type: text/html; charset=iso-8859-1

# Following that redirect gets redirected back to original
# This looks like a redirect loop except see next curl
curl -i http://band.snu.ac.kr/001246640706/.well-known/acme-challenge/Test404
HTTP/1.0 302 Found
Location: http://band.snu.ac.kr/.well-known/acme-challenge/Test404
Connection: close
Content-Type: text/html; charset=iso-8859-1

# Following that redirect (for the original URL) now does NOT get redirected 
# Instead gets the expected 404 Not Found 
# Also note the "Server: nginx" header which is not in above requests
curl -i http://band.snu.ac.kr/.well-known/acme-challenge/Test404
HTTP/1.1 404 Not Found
Server: nginx/1.18.0 (Ubuntu)
Date: Fri, 17 May 2024 13:39:34 GMT
Content-Type: text/html
Content-Length: 162
Connection: keep-alive

```

Something is probably associating the 12-digit number in your initial redirect with the IP address of the requester. Such that the subsequent requests from same IP don't get the extra redirects.

This is not a loop since it does finally resolve. But, it looks like one and Let's Encrypt protects itself by rejecting your cert request when it gets redirected back to the original URL.

---

<div class="post-metadata">

**Author:** ![Bruce5051](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/bruce5051/32/76576_2.png) [@Bruce5051](https://community.letsencrypt.org/u/Bruce5051)\
**Post date:** [May 18, 2024, 2:48am UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/7 "2024-05-18T02:48:35Z")

</div>

> [@juimdpp](#):
>
> I checked myself (with curl), I found that it works...

What version of curl did you use?

My linux one didn't see it either, to find the detail I was using

```nohighlight
>curl --version
curl 8.7.1 (amd64-portbld-freebsd13.2) libcurl/8.7.1 OpenSSL/1.1.1t zlib/1.2.13 libpsl/0.21.5 libssh2/1.11.0 nghttp2/1.61.0
Release-Date: 2024-03-27
Protocols: dict file ftp ftps gopher gophers http https imap imaps ipfs ipns pop3 pop3s rtsp scp sftp smtp smtps telnet tftp
Features: alt-svc AsynchDNS GSS-API HSTS HTTP2 HTTPS-proxy IPv6 Kerberos Largefile libz NTLM NTLM_WB PSL SPNEGO SSL threadsafe TLS-SRP UnixSockets

```

---

<div class="post-metadata">

**Author:** ![MikeMcQ](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/mikemcq/32/52772_2.png) [@MikeMcQ](https://community.letsencrypt.org/u/MikeMcQ)\
**Post date:** [May 18, 2024, 12:59pm UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/8 "2024-05-18T12:59:04Z")

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> [@juimdpp](#):
>
> because when I checked myself (with curl), I found that it works...

Probably because whatever device or software is doing the redirect with the long number already recognized your IP address. See my previous post.

The Let's Encrypt servers often use different IP addresses. If I am right about this security device / software then you will often have cert request failures. If you repeat the cert request immediately after failure it might work if you get lucky and the LE servers still have their prior IP. This is not a good thing to rely on. You should find out what is doing the faulty redirect and correct that.

Or, consider using the DNS Challenge instead. That uses DNS records rather than HTTP requests to validate your domain.

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**Author:** ![juimdpp](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/juimdpp/32/80015_2.png) [@juimdpp](https://community.letsencrypt.org/u/juimdpp)\
**Post date:** [May 19, 2024, 1:37pm UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/9 "2024-05-19T13:37:36Z")

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I'm using curl 7.68.0!

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<div class="post-metadata">

**Author:** ![juimdpp](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/juimdpp/32/80015_2.png) [@juimdpp](https://community.letsencrypt.org/u/juimdpp)\
**Post date:** [May 19, 2024, 1:39pm UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/10 "2024-05-19T13:39:54Z")

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I think you're right. Last time I wanted to renew the certificate, it kept not working then suddenly did after multiple attempts, even though I used the same command. And sometimes when I would try the same command but as a dry run (`--dry-run`), it would work...  
Thanks for the tip! I'll check if there is any other device that does some redirects!

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<div class="post-metadata">

**Author:** ![Bruce5051](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/bruce5051/32/76576_2.png) [@Bruce5051](https://community.letsencrypt.org/u/Bruce5051)\
**Post date:** [May 19, 2024, 8:16pm UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/11 "2024-05-19T20:16:22Z")

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> [@juimdpp](#):
>
> curl 7.68.0!

Try it on FreeBSD.

Also try from an external network; one that comes from outside your local area network.

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<div class="post-metadata">

**Author:** ![juimdpp](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/juimdpp/32/80015_2.png) [@juimdpp](https://community.letsencrypt.org/u/juimdpp)\
**Post date:** [May 20, 2024, 2:06am UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/12 "2024-05-20T02:06:52Z")

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Yeah! I did try it at home (outside the local area), and it shows the same thing as your result.  
I initially thought it was a firewall problem, since we originally blocked every incoming IP, but I checked with `ufw` and saw that we're currently allowing incoming access for port 80 and 443.

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<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/letsencrypt/original/3X/c/a/ca6c06ea1ea201324bba7048c6841ce60236468d.png) [@system](https://community.letsencrypt.org/u/system)\
**Post date:** [June 19, 2024, 2:07am UTC](https://community.letsencrypt.org/t/redirect-loop-detected/218510/13 "2024-06-19T02:07:27Z")

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