The VARY SYSPLEX,JOINGROUP command was rejected because either sysplex problem detection cleanup failed as the stack left the TCP/IP sysplex group, or a previous attempt to process the saved sysplex configuration and join a TCP/IP sysplex group failed. See the explanation of message EZD1194E (issued if failure occurs while processing the saved sysplex confuguration) or EZZ9675E (issued for sysplex cleanup failure) in z/OS Communications Server: IP Messages Volume 4 (EZZ, SNM) for more information.