Knowledge Base

Unable to install Let’s Encrypt certificate for the domain hosted in Plesk: SERVFAIL looking up A for example.com

Symptoms

Let's Encrypt certificate cannot be installed with the following error:

Invalid response from https://acme-v01.api.letsencrypt.org/acme/authz/DEADBEEFMwVU3eZxfBU9-PRUcd51tflRLJD7CoBTxrQ.
Details:
Type: urn:acme:error:dns
Status: 400
Detail: DNS problem: SERVFAIL looking up A for example.com

Or

Error: Could not issue a Let's Encrypt SSL/TLS certificate for example.com. Authorization for the domain failed.
Details
Invalid response from https://acme-v01.api.letsencrypt.org/acme/authz/0VWhDoTjEzzwPXNzPHd-zO73YAdXa8qgyac7eEiPQqY.
Details:
Type: urn:acme:error:connection
Status: 400
Detail: unknownHost :: No valid IP addresses found for example.com

Or

DNS problem: NXDOMAIN looking up A for example.com
- check that a DNS record exists for this domain
A website example.com may be created recently and may be accessible from the web;
Domain name cannot be resolved against some of global DNS resolvers:

# dig example.com @8.8.8.8 +short

Cause

A record does not exist or DNS propagation is not completed.

Resolution

Add A record for a domain.

If it is not clear what NS servers are managing DNS for the domain:

Go to the online NS record checker (for instance this one: Online tool for NS server check);
Check if the NS servers are the same with the Domains > exmple.com > DNS Settings. If they are, then your DNS is managed by Plesk.
If there are not matching or the option Domains > example.com > DNS Settings is absent, thus, 3-d party DNS server is used (i.e. DNS provider).

If DNS is managed in Plesk:

Log into Plesk;
Add record (type A) for the example.com in Plesk > Domains > example.com > DNS Settings > Add Record:
Click OK.

If DNS is managed by a 3d-party DNS provider:

Contact the domain provider in order to add appropriate A record

Note: If record has been already added, but the error persist, it is required to wait for a while. DNS propagation may take up to 72 hours. Use this tool in order to check global DNS propagation: DNS Propagation Check.