There should be some sort of log associated with the job. What do you find in there?
Two potential additional sources of info: the DSPDSTLOG command and the QZMF journal.
For DSPDSTLOG, you would prompt and make some educated guesses about parms such as start/end times. I can’t give much advice there without first knowing what the problems are. Look over the log entries to see if things look like you expect. Investigate things that look suspicious.
For the journal, start with WRKJRNA QZMF to get into the “receiver directory”. That should be available with <F15>. The receiver directory will give you a chance to learn if you need to review any receivers before the one that is currently attached. You can check the attributes of the most recent receivers to see if they have attach dates/times that fall in the time range you want to review. Once you know what receivers hold info about your problem, use DSPJRN QZMF to display entries from that time. Investigate things that look suspicious.
What is “suspicious”?
Hard to say. Are there very large numbers of different transactions? Is it one transaction that seems to take up all the time? Is it the same transaction(s) over and over and over?
Without looking, it’s hard to guess. Get familiar with what shows up. If you aren’t familiar, you can’t tell what shouldn’t be there.