Datacom job is failing with OPEN ERROR - RETURN CODE 76 (002) CXX=cccccccc (ara#####) MUFNAME=mmmmmmmm
OPEN ERROR 76(002) means that while opening a data set, a security validation resulted in a failure of the authorization request. This is typically related to the actual dataset security, and not External Security rules or profiles.
Verify that the MUF user (USER=uuuuuuuu on the JOB card, or the user that submitted the MUF) has the proper access to the files specified in the CXX that will be opened. Access needed is Read, Write, and Allocate for the dataset resource for the database area shown in the error message.