Sounds like an “Adoptive Authority” issue???
IN V5R4 many network actions start coming through as QUSER. It may be that QUSER isn’t authorized to the library, program or rmtcmd. Find the joblogs and see what user profile is being used. I’ve got a gripe with IBM over this and have told them frequently. Please do the same. Even with exit programs I can’t get some functions to run unless QUSER is authoirzed to your prod libs, which makes a joke of object level authority management.
If use adopted authority is set to *YES, check the system value QUSEADPAUT.
Verify no change was made there.