I'm running Exchange 2016. I configured my receive connector to require TLS and assigned a certificate to it. Now my send connector is not sending to a few domains. Event log shows event ID 2015. "The send connector requires Transport Layer Security (TLS) authentication, but is unable to establish TLS with the receiving server for the remote domain. "
In Powershell the settings are False for RequireTLS and TLSAuthLevel, TLSCertificateName and TLSDomain are blank in the send connector. When I telnet to the failing domains smtp server and type EHLO domain.com it does not show STARTTLS.
Where is my send connector getting the require TLS from? Or is it? The problem only seems to be with a few domains but it worked before I made the changes to the receive connector.