We are Using a wildcard certificate (*.domain.com)
Unable to send emails from OnPrem Exchange 2019 to external domains in Hybrid Setup.
Verified certificate thumbprint on send connector, receive connectors and transport service.
Below is the error:
Outbound TLS authentication failed with error SubjectMismatch for Send connector Outbound to Office 365 - 84a08efe-69a3-4c36-8830-6673b4fab3a7. The TLS authentication mechanism is DomainValidation. Target is gmail.com.