Do you want your Boomi process to publish directly to a dead letter queue, or do you want messages to be delivered to a dead letter queue after a number of redeliveries/failures?
Assuming the latter, you want to either enable “Create Queue and Topic Subscription” (see option’s help bubble) on your operation or manually create the dead message queue #DEAD_MSG_QUEUE.
Note that the connector does not support assigning an arbitrary DMQ. The default DMQ mentioned above must be used.