During an active monitoring session, the receiving terminal can hang rather than display a breakpoint.
The most common cause of this problem is the CA InterTest for CICS breakpoint transaction, VTAT, has received a security violation when attempting to display the breakpoint. This can often occur when the CICS transaction is not associated with a terminal and the originating terminal is defined as FROM=.ANY or FROM=.NO through the LIST Profile.
Ensure that there are no external security restrictions defined for the VTAT transaction.