2FB

Explanation
The system has abnormally ended at one of the following
points in processing: A critical error occurred early in JES3 or the functional subsystem
(FSS) initialization or late in JES3 abnormally ending. The JES3 ESTAE
environment had not yet been established or is deleted, so no JES3-formatted
ABEND dump is available.
Once JES3 initialization has successfully established the JES3
ESTAE routine (IATABMN), the retry routine (IATABRT) uses this ABEND
code to return to IATABMN in order to percolate.

An MVS™ dump will
always appear for a X'2FB' ABEND, regardless of the original
abend code.  The original abend code is shown in message IAT3713 to
the operator and in the JES3-formatted dump. The dump by itself does
not tell whether the failing JES3 function recovered or had to be
ended.
Note: An MVS dump with
a 2FB means that IATABRT or a routine used by module IATABRT failed,
thereby producing the 2FB abend.

System action
In the first case, JES3 writes message IAT3702
to the operator and to a dump data set of the type specified during
JES3 initialization.  This message details critical debugging information.

Operator response
In the first case, respond to message IAT3nnn.

System programmer response
Obtain the abend dump for the failing
job step.
If the problem occurred in JES3 you should: Save the hardcopy log
Provide a listing of the initialization deck (JES3OUT)
Provide a console log from initialization
Check the JESYSMSG data set for error indications

Programmer response
In the second case, analyze the abend dump
to find the cause of the error.

Source
JES3