23E

Explanation
During processing of a DETACH macro, the system
found an error in the input parameters.
Register 15 contains
a hexadecimal reason code that explains the error: Code
Explanation
00
The protection key of the address does not match the key of the
issuer of the DETACH.
04
Access register 1 was nonzero for a caller in access register
address space control (ASC) mode.
08
The task control block (TCB) specified in the input parameter
list is not a subtask of the caller's TCB.

System action
The system abnormally ends the program that issued
the DETACH macro.

System programmer response
  If the error recurs and the program
is not in error, look at the messages in the job log for more information.
Search problem reporting data bases for a fix for the problem. If
no fix exists, contact the IBM® Support
Center. Provide the source program listing for the job.

Programmer response
This is probably an error in the calling
program.  Change the DETACH macro to specify a valid TCB address and
ensure that it was not incorrectly modified by the problem program.
If running in access register ASC mode, ensure that the problem program
does not alter access register 1. Correct the error. Run the job again.

Source
Task management