Have you tried doing a sbmjob to run under the same user profile that you have specified on the job schedule entry?
My first thought would be to put a CHGJOB in your CL program to make sure you get a joblog :-
CHGJOB LOG(4 00 *SECLVL) LOGCLPGM(*YES)
Then see what you get in the joblog. Might also be worth checking which job queue the job goes to and whether the job queue is released and the subsystem is active. (The job has been successfully submitted but has it actually run?)