TMSTPNIT failed with User Abend U0001 and message
CAL0TN04: INTERNAL ERROR AT TMSTPNIT+00074A, CODE=...
The most common cause for this U0001 Abend is, that the AUDIT Data Set has passed the threshold. In this case you will also see the following highlighted console message:
IEFTMS9 TMC BACKUP REQUIRED, AUDIT FILE UTILIZATION IS CURRENTLY nn%
Note, the offset of TMSTPNIT, where the error occurs, can vary depending on the control statements used and on the PTF level of TMSTPNIT.
Run TMSCOPY with PARM='BACKUP' and rerun TMSTPNIT