Problem: Several Emails getting stuck in the hub ;

Solution:

• It may the DNS setting on the hub not configured or lost;
• Troubleshoot using query analyzer to get into the bottom of the issue

 

DNS Setting missing in hub :

Go to Hub transport / Select your hub server/properties & check your external DNS is configured;

Since you are there also have a look into the internal DNS lookups and ensure all is good

Further, troubleshoot using the queue viewer and selecting the hub/s