You see the error “There is currently no route to the distribution group expansion server” in a stuck message from your Exchange Hub Transport server submission queue.
To resolve this:
- Make note of the distribution group in the recipient information tab.
- Search for the Distribution Group in Exchange Management Console
- Right click on the group and choose properties
- Go to the Advanced tab
- Untick the box next to “Set expansion server”
You might have to restart the Hub Transport or SMTP service depending on your Exchange version.
We found this happened because the Expansion server was removed from the environment and not accessible. Another cause could also be the deletion of a routing group in Exchange 2003.