I have recently migrated our office to SBS 2011. We wanted to get rid of the POP3 service and decided to go with Positini. I have all users setup on positini, mx records are passing the tests and setup. Watchguard firewall is using NAT translation from our outside IP address to the SBS server. I am using outside IP address for delivery on the inbound server. I have added the IP addresses for receiving mail on the internal sbs internet receive connector.
When I do the SMTP tests on the Positini site I am getting sucessful results but also getting the 500 error RCP To, check firewall or email server is down. This will happen randomly on any user. Also I am seeing these errors with the normal email as well. It is hit and miss. I am leaning toward something I am not doing on the exchange connector.
Any ideas and thanks in advance!!! Also if I am leaving out some information that would be helpful let me know!!!
I sent an email just now went through. Sent again to another user here is the error message
Unable to send SMTP message test: 550 - RCPT TO failed.
The email server is not available. Check your firewall or email server for settings that might be preventing delivery.