Usually caused by a client application not processing results from the SQL Server quickly enough, or the client application processing data row by row instead of using SQL Server to handle the complex filtering and joins.
Possibly a network issue, but most likely the client application is the cause of the wait.
This is often times caused by Microsoft Access pulling down more data from the SQL Server than it should.
- Reboot the client (even if it’s web server)
- Check the amount of available memory for the client application
- Ensure NICs are set correctly (firmware, full duplex etc)