I get error 5.7.1 Unable to relay when i try to send from an internal server to an external domain. This issue is only occuring on one of the newly deployed servers( i will call it server X). i have no issue sending from server x to internal domain users.
When I checked the message tracking tool, i found that server X uses the default receive connector while all other servers use the custom receive connector (server connector). I don't know if this is the main cause of the problem, but all other servers that are using (server connector) can send to external domain normally. I have added Server X ip to the remote ip list.
The receive connectors are configured as follow:
- Default connector and server connector, have the same IP address and same port 25
- Default connector Permissiongroup :AnonymousUsers, ExchangeUsers, ExchangeServers, ExchangeLegacyServers
-Server connector permissiongroup : AnonymousUsers, ExchangeUsers, ExchangeServers
-Default connector Authentication: Basic,Exchange server,Integrated Windows
-Server connector Authentication : TLS. Externally secured