# ConnectionError: HTTPSConnectionPool(host=’acme-v02.api.letsencrypt.org’, port=443)
**URL:** https://community.letsencrypt.org/t/connectionerror-httpsconnectionpool-host-acme-v02-api-letsencrypt-org-port-443/92236
**Category:** Help
**Created:** [April 27, 2019, 2:06am UTC](https://community.letsencrypt.org/t/connectionerror-httpsconnectionpool-host-acme-v02-api-letsencrypt-org-port-443/92236 "2019-04-27T02:06:16Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@luongtienltc](https://community.letsencrypt.org/u/luongtienltc)
#### Post date: [April 27, 2019, 2:06am UTC](https://community.letsencrypt.org/t/connectionerror-httpsconnectionpool-host-acme-v02-api-letsencrypt-org-port-443/92236/1 "2019-04-27T02:06:16Z")
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: [dendietcontrung.net](http://dendietcontrung.net)
I ran this command: /opt/letsencrypt/certbot-auto certonly –standalone
It produced this output:
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator standalone, Installer None
An unexpected error occurred:
ConnectionError: HTTPSConnectionPool(host=’[acme-v02.api.letsencrypt.org](http://acme-v02.api.letsencrypt.org)’, port=443): Max retries exceeded with url: /directory (Caused by NewConnectionError(‘: Failed to establish a new connection: [Errno -3] Temporary failure in name resolution’,))
Please see the logfiles in /var/log/letsencrypt for more details.
My web server is (include version): Cloud server
The operating system my web server runs on is (include version): Linux
My hosting provider, if applicable, is: Viettel idc
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):
---
### Author:  [@mnordhoff](https://community.letsencrypt.org/u/mnordhoff)
#### Post date: [April 27, 2019, 2:27am UTC](https://community.letsencrypt.org/t/connectionerror-httpsconnectionpool-host-acme-v02-api-letsencrypt-org-port-443/92236/2 "2019-04-27T02:27:59Z")
> [@luongtienltc](#):
>
> [Errno -3] Temporary failure in name resolution
Is the server's DNS resolver working?
If you run "`dig acme-v02.api.letsencrypt.org`" or "`dig www.google.com`", what's the output?
---
### Author:  [@luongtienltc](https://community.letsencrypt.org/u/luongtienltc)
#### Post date: [April 27, 2019, 2:53am UTC](https://community.letsencrypt.org/t/connectionerror-httpsconnectionpool-host-acme-v02-api-letsencrypt-org-port-443/92236/3 "2019-04-27T02:53:34Z")
When i run “dig [acme-v02.api.letsencrypt.org](http://acme-v02.api.letsencrypt.org)” the output is
; \<\<\>\> DiG 9.9.4-RedHat-9.9.4-61.el7\_5.1 \<\<\>\> [acme-v02.api.letsencrypt.org](http://acme-v02.api.letsencrypt.org)
;; global options: +cmd
;; connection timed out; no servers could be reached
---
### Author:  [@luongtienltc](https://community.letsencrypt.org/u/luongtienltc)
#### Post date: [April 27, 2019, 5:07am UTC](https://community.letsencrypt.org/t/connectionerror-httpsconnectionpool-host-acme-v02-api-letsencrypt-org-port-443/92236/4 "2019-04-27T05:07:01Z")
When i run “dig [www.google.com](http://www.google.com)” the out is"
; \<\<\>\> DiG 9.9.4-RedHat-9.9.4-61.el7\_5.1 \<\<\>\> [www.google.com](http://www.google.com)
;; global options: +cmd
;; Got answer:
;; -\>\>HEADER\<\<- opcode: QUERY, status: NOERROR, id: 12301
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;[www.google.com](http://www.google.com). IN A
;; ANSWER SECTION:
[www.google.com](http://www.google.com). 300 IN A 172.217.194.106
[www.google.com](http://www.google.com). 300 IN A 172.217.194.103
[www.google.com](http://www.google.com). 300 IN A 172.217.194.104
[www.google.com](http://www.google.com). 300 IN A 172.217.194.105
[www.google.com](http://www.google.com). 300 IN A 172.217.194.147
[www.google.com](http://www.google.com). 300 IN A 172.217.194.99
;; Query time: 27 msec
;; SERVER: 115.84.181.20#53(115.84.181.20)
;; WHEN: Sat Apr 27 11:59:41 +07 2019
;; MSG SIZE rcvd: 128
Please advise
---
### Author:  [@mnordhoff](https://community.letsencrypt.org/u/mnordhoff)
#### Post date: [April 27, 2019, 5:28am UTC](https://community.letsencrypt.org/t/connectionerror-httpsconnectionpool-host-acme-v02-api-letsencrypt-org-port-443/92236/5 "2019-04-27T05:28:40Z")
That’s strange.
What happens if you try “`dig acme-v02.api.letsencrypt.org`” several times, and:
```
dig eff.org
dig golang.org
dig letsencrypt.org
dig mozilla.org
```
---
### Author:  [@JuergenAuer](https://community.letsencrypt.org/u/JuergenAuer)
#### Post date: [April 27, 2019, 6:56am UTC](https://community.letsencrypt.org/t/connectionerror-httpsconnectionpool-host-acme-v02-api-letsencrypt-org-port-443/92236/6 "2019-04-27T06:56:15Z")
Hi @luongtienltc
> [@luongtienltc](#):
>
> ; \<\<\>\> DiG 9.9.4-RedHat-9.9.4-61.el7\_5.1 \<\<\>\> [acme-v02.api.letsencrypt.org](http://acme-v02.api.letsencrypt.org)
> ;; global options: +cmd
> ;; connection timed out; no servers could be reached
looks like your local dns is buggy. May be a problem of your configuration, may be a problem of your hoster.
Do you have an old, now wrong hosts - entry?
Perhaps add
```nohighlight
23.63.149.194 acme-v02.api.letsencrypt.org
2a02:26f0:fc:290::3a8e: acme-v02.api.letsencrypt.org
```
in your hosts file.
---
### Author:  [@system](https://community.letsencrypt.org/u/system)
#### Post date: [May 27, 2019, 6:56am UTC](https://community.letsencrypt.org/t/connectionerror-httpsconnectionpool-host-acme-v02-api-letsencrypt-org-port-443/92236/7 "2019-05-27T06:56:16Z")
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