Sophos Email Setting - Mail Spool

Hello.

Need help with Sophos XGS136 Firmware 19, 

I have enabled email protection and created a on prem mail server, I don't have problem for external domain to reach the mail server. It would be able to received mails.

My problem is from the on prem mail server it would be able to be spooled inside sophos but would not be able to send.

These are the errors:

  - R=static_route_bymx_for_email T=remote_smtp defer (-53) DT=0.000s: retry time not reached for any host for 'XXX'.    *XXX is domain

  - xyz @ gmail. com routing defer (-51) DT=0.000s: retry time not reached

I was able to read https://support.sophos.com/support/s/article/KB-000038662?language=en_US#9.-Mails-are-not-delivering-and-getting-an-error-%E2%80%9Cdefer-(-53):-retry-time-not-reached-for-any-host%E2%80%9D

but It was not able to resolve my error.