AD2U abend in CICS. THREADERROR 906

AD2U abend in CICS OR THREADERROR 906

AD2U abend occurs when DB2 thread creation fails.

Resolution:-
Check the SQLCODE associated with the abend.
THREADERROR 906 is the common SQLCODE with AD2U. Application may return the different SQLCODE,
SQLCODE 922 indicates the authorization error - i.e. given user does't have authorization on given plan in given region.

So verify your plan, its access and also verify the RCT entries for application's transaction for given plan.