Trouble Renewing SSL Certificates: Name Resolution Error

Hello everyone,I'm encountering an issue while attempting to renew SSL certificates with Let's Encrypt using the nginx-proxy-manager application on my truenas scale server. Whenever I try to renew the certificates, I receive a NameResolutionError indicating a failure in name resolution for

Error Message:

HTTPSConnectionPool(host='', port=443): Max retries exceeded with url: /directory (Caused by NameResolutionError("<urllib3.connection.HTTPSConnection object at 0x7f8502786b50>: Failed to resolve '' ([Errno -3] Temporary failure in name resolution))"Timestamp: 2024-02-17 12:30:06.598875+01:00

I've ensured that my server has proper network connectivity and can access the internet. Additionally, I've checked the DNS resolution and confirmed that other domain names resolve correctly.Could anyone please provide guidance on how to troubleshoot and resolve this issue? Any insights or suggestions would be greatly appreciated.

Thank you in advance for your assistance!

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Hi @Hika, and welcome to the LE community forum :slight_smile:

That is a DNS issue that is unrelated to the FQDN you are trying to resolve [].

What shows?:

  • cat /etc/resolv.conf
  • dig +short
  • dig +short @

Hello :wave:,

Here are more details:


  • When checking the DNS resolution settings on my server, everything seems to be configured correctly.
  • The /etc/resolv.conf file contains the correct DNS server entries ( and
  • I've tested DNS resolution using dig commands, and it appears that DNS resolution is working fine when querying external domains like and using the DNS server
  • However, the issue persists when trying to obtain SSL certificates, indicating that there may be an issue with DNS resolution from my server itself.
  • It's worth noting that my Docker container typically does not use custom DNS configuration.
admin@TrueNas[~]$ cat /etc/resolv.conf
domain local
admin@TrueNas[~]$ dig +short
admin@TrueNas[~]$ dig +short @

I would appreciate any guidance or assistance you can provide in resolving this issue. If you need any further information, please let me know.

Thank you for your attention to this matter.:heart:

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It sounds like you are running certbot within a docker container.
If so, then the failed DNS requests are coming from within that container.
I don't know much about docker and how it provides DNS service to its' containers.
I'm almost certain you can get faster help with this type of problem from a docker forum.


Ok thank you very much for taking the time to answer me and for responding so quickly :+1:

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