Check your GWIA log files, if you don't have logging enabled, enabled it and replicate the problem. Even better if you have the log in VERBOSE mode. Just make sure you have plenty of space on the volume. The MTA log will be helpfull also.
What you are looking for is the message being sent out. First look at the GWIA log file and find the message being transmitted; this will give you the message ID, this will allow you to find the message being transferred out of the MTA. Then you want to look back into the GWIA for the return message. If the domain is truly valid, and the returned mail is sourcing from the recipients mail server, then you will see a return message and you will see the dialogue spoken between the two servers. You will also get the message ID, you can trace this to the MTA.
Look at the time stamps of all these items. If the time stamps between the MTA > GWIA > INTERNET are with in good ranges then sending is not a problem. If the time stamps going from the INTERNET > GWIA > MTA are in good ranges then reciving is not a problem. Look at the time stamps between the time your server sent the message and the return message came in. If the gap is there, there is little you can do your self.
One option would be to contact the IT at the recipients location to see if they will run similar tests on their system.
Also look at your GWIA config, make sure you are sending directly to the recipients mail server, not using a mail relay server. Not much need for a mail relay server with GroupWise. Brent Schmidt CNE, Network +
Senior Network Engineer
Why do user go into a panic when a NetWare server goes down, but accept it as normal when a Windows server goes down?