You can wait for the current request to finish and try again. You can also detach the existing requests stopped for debugging using dbg:detach. Another option is to increase the number of allocated threads for debugging by changing the debug threads
option on the task server. This will cause a server restart and changes will only become effective after the restart.
No expression is found matching the request id and expression id passed to dbg:expr.
Make sure that the request id and expression id passed to dbg:expr are correct.