DFS1278E LUMx POOL LIMIT REACHED, ALL APPC INPUT WILL BE REJECTED.
Explanation
The LUMP or LUMC storage pool has less than 1 MB of free storage. In the message text, x can be either P or C.
System action
IMS tells APPC/MVS to reject all advanced program-to-program communication (APPC) input until the pool has more than 5 MB of storage. APPC input that is already processing can continue.