I THink the DKIM signing is based on The "Sender" Header.Can you please try with Sender header:MAIL FROM:<xxx@foo.com>RCPT TO:<kdrexg-dktest@test.myiptest.com>DATAFrom:<xxx@foo.com>To:<kdrexg-dktest@test.myiptest.com>sender: <xxx@foo.com>Subject:test...

ALso try to ping with the IP/Hostname. In case the DNS is not able to resolve the encryption server name, the IP PING should work.

I'd suggest first going to CLI and checking PING connectivity to the encryption server.If ping is working, we can rule out netowrk connectivity and gateway/route issues.The other thing you can probably try ( if ping works ), is to see if you need a p...