This problem is happening on the mainframe side and you must consult with XCOM mainframe support and IBM RACF support to find out what is happening.
You can determine where the message is originating, by looking at the 5th character in the message. For example, XCOMM5516E. The M indicates this message originated on MVS (or mainframe).
This error message is being issued by RACF and being passed back from mainframe XCOM to XCOM on Windows.