Managing the Event Handler 
If the WSRM Event Handler is active, events that occur in connection with Web Services Reliable Messaging are processed. To be able to cancel sequences using the Sequence Monitor, the WS-RM Event Handler must be functioning without error.
Procedure
In SAP NetWeaver Administrator, choose
Sequence Monitoring 
Event Handler Administration 
.Choose Event Handler Active? to check if the Event Handler is running.
If not, select Start Event Handler.
You can stop the Event Handler in order to troubleshoot errors.
(More information: Monitoring Event-Controlled Processing)
The WS-RM Event Handler is started by the AUTOABAP process. This process produces child processes when a WSRM event is performed. The standard value is 3. The number of these processes can be configured using the RSEHCONFIG report. In the Maximum Allowed Processes field, enter a 0 and choose F8 to stop the Event Handler - for example, for troubleshooting. When troubleshooting is finished, restart the Event Handler.