A task might fail to get attached to the transaction manager for one of the following reasons:
Guidance about investigating these possibilities is given in Investigating interval control waits. You need to consider doing this only if INTERVAL or TIME was specified on the START command.
Remember that several tasks might be queued on the terminal, some of which might require operator interaction. In such a case, the transaction to be started might not get attached to the transaction manager for a considerable time.
You can use CEMT INQ TERMINAL to inquire on the status of the remote system.