There is too much central storage. In z/Architecture® mode, the maximum amount of storage is 4 terabytes.
Central storage reconfiguration is disabled, and the Display M command may produce unpredictable results. The system issues message IEE021A and continues its initialization process.
Contact the system programmer.
Reduce the installed storage to the maximum allowed (4 TB for z/Architecture mode), then re-IPL the system to enable storage reconfiguration.
Reconfiguration.
IEERMAXW