BND2178E Unable to connect to subsystem `ssid` RC= `return code`, REASON= `reason code`

Explanation
 An unexpected Db2® error
occurred while ADBBMRG tried to connect to the specified subsystem.

ssid
The subsystem ID.

return code
The return code from Db2.

reason code
The reason code from Db2.

Module: ADBBMRG
System action
Processing stops.
User response
Ensure that the subsystem is up and available.

BND2178E Unable to connect to subsystem ssid RC= return code, REASON= reason code