X'1018' MSGIDSTN BLOCK NOT CNT/LNB/QAB

Explanation
The control block returned by FINDEST, representing the source name at
MSGIDSTN, is not a CNT (LTERM), LNB (MSNAME), or QAB (LU 6.2 node).

Programmer response
Locate the MSGIDSTN name in the message and verify that it is a valid LTERM,
MSNAME, or LU 6.2 node. If it is an LU 6.2 node, then MSGIDSTN begins with FEFFFFFF and the NODE name is in the LU 6.2 prefix. The control block
address is in REG1 in the REG14-12 save area, and the block is at QTPDST.