Setting up an ssl certificate on WMS

Hello, I'm in the process of configuring my On-Premise WMS server. When configuring the SSL certificate, I get an error that I don't understand. I've tried to go through all the log files (Tomcat, ...) without finding the least error related to this. These are certificates obtained from a public certification authority, which sends me the key pair / PEM-encoded certificate directly. I don't enter any password, none has been defined. Below are some screenshots showing my problem.

I recently changed the server's FQDN (DNS entry) and therefore have a certificate associated with this new FQDN. Do you think this is a problem?

Regards