Domain is not secured over WWW even though Let's Encrypt certificate is installed

Dinara Tsydenova

Updated September 17, 2023 18:14

Plesk for Windows Plesk for Linux kb: technical ext: le ABT: Group A

Applicable to:

Warning in browser is shown whenever the domain with installed Let's Encrypt SSL is accessed with www-prefix like https://www.example.com:
CONFIG_TEXT: NET::ERR_CERT_AUTHORITY_INVALID

CONFIG_TEXT: Your connection is not private
This server could not prove that it is www.example.com; its security certificate is from example.com. This may be caused by a misconfiguration or an attacker intercepting your connection.
Certificates is shown "WWW domain not secured" under Domains > example.com > SSL/TLS Certificates

The certificate was issued only for the domain example.com, without www-prefix.

Reissue certificate with www-prefix:

Login to Plesk;
Open Domains > example.com > SSL/TLS Certificates
Check the option Include a "www" subdomain for the domain and each selected alias
Click Reissue Certificate.