Just recently we got a questions about a failing REXX/VSE GETMSG function.
GETMSG may fail with function code 8 and the message "ARX565I MCSOPMSG FAILED RC=(0012,000)" meaning that the console is suspended. A REXX program can react on a suspended console by deactivating this console
and activating it again. I don't go into more detail for now, instead want to point you to the z/VSE Hints and Tips book. There you can find more details on how to resolve that situation, see chapter REXX/VSE, section "Console Command Environment".
The z/VSE Hints and Tips book is provided by the z/VSE development team. You can download it here.