If an encrypted SSL connection is used, the name of server with forpsi.com has to be used

To ensure proper functioning of the encrypted SSL communication between email clients and email servers, there are created certificates for the domain names, under which the servers are known and published in the internet; specifically for the names pop3.forpsi.com, imap.forpsi.com and smtp.forpsi.com.

For this reason, it is necessary to use the names of the servers with forpsi.com (pop3.forpsi.com, imap.forpsi.com, smtp.forpsi.com).
Certificates are valid for one year. After that, new certificates must be issued. If you have set the names of servers with your domain in your email client, your email client might ask you to allow exception for new certificates (they are issued for pop3.forpsi.com ..., not for pop3.yourdomain.tld ...). You can prevent these alerts if you use only the names of servers with forpsi.com.