Invalid response from

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., so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.

My domain is:
I ran this command:
sudo certbot --nginx
It produced this output:
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator nginx, Installer nginx
Starting new HTTPS connection (1):

Which names would you like to activate HTTPS for?


Select the appropriate numbers separated by commas and/or spaces, or leave input
blank to select all options shown (Enter ‘c’ to cancel): 1
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for
Waiting for verification…
Challenge failed for domain
http-01 challenge for
Cleaning up challenges
Some challenges have failed.


My web server is (include version):
nginx version: nginx/1.16.0
The operating system my web server runs on is (include version):
CentOS Linux release 7.5.1804 (Core)
My hosting provider, if applicable, is:
I can login to a root shell on my machine (yes or no, or I don’t know):
I’m using a control panel to manage my site (no, or provide the name and version of the control panel):
The version of my client is (e.g. output of certbot --version or certbot-auto --version if you’re using Certbot):
certbot 0.35.1
the /var/log/letsencrypt/letsencrypt.log validationRecord is:
“validationRecord”: [
“url”: “”,
“hostname”: “”,
“port”: “80”,
“addressesResolved”: [
“addressUsed”: “2600:1901:0:5f0f::”
my nginx config is:

server {
listen [::]:80;
listen 80;

#charset koi8-r;
access_log  /var/log/nginx/host.access.log  main;

location / {
    root   /usr/share/nginx/html;
    index  index.html index.htm;

location /AppflyerNotify{
    proxy_set_header Host $host:$server_port;
    proxy_set_header X-Real-Ip $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

#error_page  404              /404.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;

# proxy the PHP scripts to Apache listening on
#location ~ \.php$ {
#    proxy_pass;

# pass the PHP scripts to FastCGI server listening on
#location ~ \.php$ {
#    root           html;
#    fastcgi_pass;
#    fastcgi_index  index.php;
#    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
#    include        fastcgi_params;

# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#location ~ /\.ht {
#    deny  all;


my /var/www dir is empty

Hi @hackerys

checking your domain there are Google-ip addresses -

Host T IP-Address is auth. ∑ Queries ∑ Timeout A

Newark/New Jersey/United States (US) - Google LLC
Newark/New Jersey/United States (US) - Google LLC|yes||

What's the ip address of your system?

Checking your urls there are different answers:

Domainname Http-Status redirect Sec. G 200 0.220 H
2600:1901:0:5f0f:: 404 0.043 M
Not Found -14 10.030 T
Timeout - The operation has timed out
2600:1901:0:5f0f:: -4 0.073 W
SendFailure - The underlying connection was closed: An unexpected error occurred on a send. Authentication failed because the remote party has closed the transport stream. -14 10.013 A
Timeout - The operation has timed out
Visible Content:
2600:1901:0:5f0f:: -8 0.084 A
ConnectionClosed - The underlying connection was closed: The connection was closed unexpectedly.
Visible Content: 404 0.226 A
Not Found
Visible Content: 404 Not Found nginx/1.16.0
2600:1901:0:5f0f:: 404 0.046 A
Not Found
Visible Content: Error 404 (Not Found)!!1 404. That’s an error. The requested URL /.well-known/acme-challenge/check-your-website-dot-server-daten-dot-de was not found on this server. That’s all we know.

/.well-known/acme-challenge - ipv4 is a standard-nginx - answer, ipv6 is a typical Google-answer.

Looks like your ipv6 doesn't work.

1 Like

Thank you very much for your reply. After I tried to close the ipv6 resolution of the domain name, the certbot command was successfully executed.:+1:


This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.