Two domains cannot email each other (Full Version)

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dstafford1701 -> Two domains cannot email each other (4.Jun.2015 9:52:20 AM)

I have a recent install of Exchange 2013 with mail filtering through a Sophos UTM, everything works as it should, except I have one domain that cannot email mine, and my domain cannot email it. Both of these servers reside in the same geographical region, use the same ISP, and use public static IP addresses that only differ by the last octet (though they reside on different subnets).

DNS can resolve the exchange server I am trying to send to however emails queue and eventually end with an NDR.

SPF records are set up properly with external DNS provider.

"Remote server at ________ returned '400 4.4.7 Message delayed' <date and time> - Remote server at ______ returned '441 4.4.1 Error encountered while communicating with primary target IP address: "Failed to connect. Winsock error code: 10060, Win32 error code: 10060." Attempted failover to alternate hosts. The last endpoint attempted was <IP address of their domain:25'

Originally thought this may have been an issue with PTR records, had the ISP fix the PTR records for both of the company's Exchange servers, however that change did not resolve the issue. At this point I have run out of ideas.

nuggetfarm -> RE: Two domains cannot email each other (11.Jun.2015 2:27:41 AM)

Are these domains in a co-existent namespace? Or are they two completely different organisations?



Edwin009 -> RE: Two domains cannot email each other (23.Apr.2019 2:41:12 PM)

Get the source domain name from where its emailing and getting error.
Do a tracert from server and check if there is connectivity between source and destination.
Try to ping from source server to your server where its sending emails.
The results should show where is the error.
You could also telnet to port 25 and test SMTP.

Ed |Tech Support Team

Cloud based QuickBooks -

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