A significant number of DNS queries have been requested by user %1. There have been %2 queries in the last %3 minutes. There ...

A significant number of DNS queries have been requested by user %1. There have been %2 queries in the last %3 minutes. There have been %4 errors in total.
Resolution:
This generally happens because the user has a lot of invalid contacts or is attempting to reach a large number of different federation domains that don't exist. This user could also be attempting to overload the server by issuing queries that won't resolve or won't resolve quickly. It is recommended that this user's traffic be analyzed to understand why they are making so many requests and to determine if this is actually an application that is enumerating through domain space and should be turned off.