Hi Anita,
Offline backup is completed successfully but not able to take online backup.
after some analysis mount point in aix related like sapdata1-n, logs and archive are not mounted with option read read and cio, may this is the issue.
in note 948294 the mount point should be with option cio, but not sure beacuse take downtime to remount all.
After this only will sure whats the root cause for the same.
Regards
Naveen