Can you reproduce the problem?

If we can reproduce the problem, consider the conditions under which you can reproduce it. For example:

Is it caused by a command?

If so, is the command issued from the z/OS console, from CSQUTIL, from a program written to put commands onto the SYSTEM.COMMAND.INPUT queue, or by using the operations and control panels?

Does the command work if it is entered by another method?

If the command works when it is entered at the console, but not otherwise, check that the command server has not stopped, and that the queue definition of the SYSTEM.COMMAND.INPUT queue has not been changed.

Is the command server running?

Issue the command

DIS CMDSERV to check.

Is it caused by an application?

If so, does it fail in CICS, IMS, TSO, or batch?

Does it fail on all WebSphere MQ systems, or only on some?

Is an application causing the problem?

Can you identify any application that always seems to be running in the system when the problem occurs? If so, examine the application to see if it is in error.