Can't send email - this is regularly occurring problem See error msg below

Once or twice a year, I get the following error message saying that the Host Name doesn't match the certificate and won't let me send a message from this mailbox.  This is not a one time thing  but has happened multiple times over the years and causes a great deal of inconvenience since my "Sent" box indicates the message has been send but it doesn't reach the intended recipient.  We usually end up calling support and they do something to fix it on their end but it's an ongoing problem