Logging on to CMEW after upgrading to Endevor release 16.0 or higher may fail.
The spawned task is failing with security error on temporary dataset for ddname APIMSGS::
ICH408I USER(<ID> ) GROUP(<GROUP> ) NAME(<USER>)
SYS.D#####.T#####.#####.APIMSGS CL(DATASET ) VOL(vol)
332 DEFINE - INSUFFICIENT AUTHORITY
Solution is to modify the C1DEFLTS parameter MODHLI to change the hlq of that dataset.