Could not obtain directory: cURL error 6: Could not resolve host:; Unknown error

im using Plesk Obsidian 18.0.29 Update1 / Centos 7 and try to request for my plesk panel an LetsEncrypt Certificate. When requesting the Cert i get the error message:

Error: Could not issue a Let’s Encrypt SSL/TLS certificate for XYZ .

Failed to connect to the Let’s Encrypt server .
Please try again later or report the issue to support.

Could not obtain directory: cURL error 6: Could not resolve host:; Unknown error (see

Any Idea how to solve this?
Thank You!

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Hi @Salli

your machine has a wrong / missing dns / network configuration.

So it’s impossible to find the ip address of the api endpoint.

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Hello Juergen,

thanks for the information. Strange, Resolving Servers Hostname via IP / Name Public works perfect, what else could be the issue?

Im using Let’s Encrypt Extension from Webcataloge Version 2.11.1-640

Best regards

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Testing nslookup from the server:


Non-authoritative answer: canonical name = canonical name =
Address: 172.65.x.x
Address: 2606:4700:60:0:f53d:5624:85c7:3a2c

You should probably try again, it could have been a transient issue.

Tried yet again, same error when requesting the Cert

If you use Plesk and if Plesk can’t connect Letsencrypt, then ask your hoster.

Then your Plesk configuration doesn’t work. But that’s a Plesk / server internal problem.

Plesk can connect as the requests for the Domains work without any issue. But the Admin Panel request for the Host Name still fail…

And that’s the problem. Or you have an internal misconfiguration. Or the Admin panel uses another name server (not your working manual nslookup).

The Domains are managed as well by the Admin Panel, so the Panel dont use a own or different name server. And the lookup for the API Endpoint from the Server works as I send above. Is there anything else what I could test ?

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