I've an Exchange 2013 Server with two wildcard certificates, one for matching the internal AD zone and the other one with the public domain.
The certificates are defined with those names:
*.example.com
*.local.example.com
When I try to connect through the Submission port (587) the presented certificate is the one of the zone *.local.example.com which ends complaining about the hostname mismatch of the service.
IMAP service works as expected with the correct *.example.com certificate, but SMTP don't.
Already tried things like Enable-ExchangeCertificate on Powershell to remove the SMTP service from the certificate, but it does not work.
Best Answer
Don't try and force which certificate is used. You can have multiple certificates enabled for SMTP, so set them all to be enabled for that service. The actual certificate is then set by the FQDN on the Receive Connector. Don't change the FQDN value on the Default Connector, as that will cause problems.