Do you know how I can resolve The problem below?
This scenario was normally working few months...
Exchange 2016
SMTP client is trying to send email by port 25 using TLS and Basic auth. Recive connector authenticate user and make proxy to Reciver Client Proxy.
Client Proxy quit connection and provide information:
Setting up client proxy session failed with error: 451 4.4.0 Primary target IP address responded with: ""451 4.5.0 Require XAnonymousTls to send mail.
I can't find solution for that.