WebSphere MQ Log Locations
If the queue manager name is known and the queue manager is available, WebSphere MQ error logs are located in the directory specified by the LogPath parameter defined in the queue manager configuration file qm.ini. If the queue manager is not available, error logs are located in: /var/mqm/qmgrs/@SYSTEM/errors. If an error has occurred with a client application, error logs are located on the client’s root drive in: /var/mqm/errors.
If your application gets a return code indicating that a Message Queue Interface (MQI) call has failed, refer to the WebSphere MQ Application Programming Reference Manual for a description of that return code.