Here is an example of error AMQ9511E. This error is usually found in /var/mqm/qmgrs/your_queue_manager/errors/AMQERR01.log.

AMQ9511E: Messages cannot be put to a queue.

EXPLANATION:
The attempt to put messages to queue 'your_queue' on queue manager 'your_queue_manager' failed with reason code 2009.

ACTION:
Ensure that the required queue is available and operational.

Ensure the queue manager is running

Use the dspmq command to ensure the queue manager is running.

QMNAME(MANAGER01)    STATUS(Running)

Determine when the queue manager was last restarted

Use the display qmstatus command to determine when the queue manager was last restarted. Stopping or restarting the queue manager can cause reason code 2009. In this example, MANAGER01 was started on 3/12/2020 at 15.51.36 (that's 3:51 pm).

echo "DISPLAY QMSTATUS STARTDA STARTTI" | runmqsc MANAGER01

  STARTDA(2020-03-12)   STARTTI(15.51.36)

Ensure the queue manager has not reached maximum channels

The maximum channels are configured in the /var/mqm/qmgrs/your_queue_manager/qm.ini file, like this.

Channels:
  MaxChannels=100

The following command will return the currently number of active channels to the queue manager.

echo "DISPLAY CHSTATUS(*)" | runmqsc your_queue_manager | grep 'AMQ8417' | wc -l

Keep Alive

Ensure /var/mqm/qmgrs/your_queue_manager/qm.ini has the following configuration.

TCP:
  KeepAlive=YES

Firewall

If there are firewalls between the queue and the system putting messages on the queue, ensure the firewalls are configured to allow connections to the queue.