Good morning,
I have my second mailbox server that gets this error. I can seem to do everything on this server, but would like to get it up and running stable.
Error:
An authentication credential initialization error TLS1_0NotSupported occurred with Send connector Mailbox Proxy Send Connector. The authentication mechanism used was ExchangeAuth. The name of the server that we were trying to authenticate to was SMTPSVC/MAILBOXServer2.
This server was using the name NT AUTHORITY\SYSTEM. Try reentering the credential. If the problem persists, contact Microsoft Support Services.
Thanks