Getting ora-01555 on expdp

While performing a full export I'm getting the below error:

ORA-31693: Table data object "SYSTEM"."SCHEDULER_PROGRAM_ARGS" failed to load/unload and is being skipped due to error:

ORA-29913: error in executing ODCIEXTTABLEPOPULATE callout

ORA-01555: snapshot too old: rollback segment number 23 with name "_SYSSMU23_1332513299$" too small

I have increased undo_retention to 4 hours and the UNDO tablespace can extend up to 96GB.

But the error keeps coming.

Strange message:

Table data object "SYSTEM"."SCHEDULER_PROGRAM_ARGS" failed to load/unload

"SYSTEM"."SCHEDULER_PROGRAM_ARGS" is a view and returns only 12 rows.

Any idea? DB version is 12.1