Is the queue manager showing a lot of CPU activity?

Try to enter an MQSC DISPLAY command from the console. If you get no response, it is possible that the queue manager is looping. Follow the procedure shown in Has your application or WebSphere MQ for z/OS stopped processing work? to display information about the processor time being used by the queue manager. If this indicates that the queue manager is in a loop, cancel it with a dump and restart.

If the problem persists, refer to Finding solutions to similar problems and Working with IBM to solve your problem for information on reporting the problem to IBM.