I noticed in the event viewer that there was an error related to a certificate.
Microsoft Exchange could not find a certificate that contains the domain name SERVERNAME.domainname.com in the personal store on the local computer. Therefore, it is unable to support the STARTTLS SMTP verb for the connector Default SERVERNAME with a FQDN parameter of SERVERNAME.domainname.com. If the connector's FQDN is not specified, the computer's FQDN is used. Verify the connector configuration and the installed certificates to make sure that there is a certificate with a domain name for that FQDN. If this certificate exists, run Enable-ExchangeCertificate -Services SMTP to make sure that the Microsoft Exchange Transport service has access to the certificate key.
After checking the certificates, I noticed that the "Microsoft Exchange" Self Signed cert is missing from the list of certificates. I checked all the other servers and they all have that cert so the issue is only on the one server. Does anyone know how I can recreate that certificate so I can fix this error?