Symptoms
SSL privacy warning is shown when accessing Plesk panel UI using customer’s domain name at https://example.com:8443:
Your connection is not private
or:
NET::ERR_CERT_COMMON_NAME_INVALID
or:
Connection not secure
Cause
This is expected behaviour. Plesk interface is secured by an SSL issued to the server hostname. Other domains, like example.com, had their own certificates that are issued for a particular domain name. So https://example.com will show valid SSL issued for example.com, while https://example.com:8443 will detect that SSL for example.com is not the same as for the server hostname.Â
Resolution
To avoid the privacy warning, access Plesk using main server hostname URL secured by Let’s encrypt. For example, if the hostname is hostname.com, the link will be https://hostname.com:8443.
The link may be used by any customer, domain owner, reseller, or administrator.
Alternatively, issue the UCC SSL certificate covering several domains from any convenient SSL authority. After that install this certificate using instructions.
Additional information
How to use different SSL certificates for Plesk UI (over port 8443)?