Default Configuration for a user is a collection sets of configurations that have to be read from the database. Is your SQL server that host the BESMgmt database have latency issue with the computer that runs the BAS?
Check the snip from
KB24632 below:-
"To maximize the performance of the BlackBerry Administration Service and
avoid slow response times, computers that host the BlackBerry Administration Service should be placed in the same data center as the Microsoft® SQL Server® that hosts the BlackBerry Configuration Database. Round-trip latency should be less than
20 milliseconds."
Source:
KB24632-Performance considerations for the BlackBerry Administration Service