3303514 - Dialog instance cannot connect to Message Server

In the SAP MMC, the status of dialog instance is YELLOW with warning info "Running but not connected to Message Server".

The same information can be seen on a "sapcontrol" command with function "GetProcessList".

Scenario 1: although this yellow state is present, the dialog instance is accessible and working normally.

Scenario 2: the dialog instance is not operational.

In this case, the Dispatcher trace file shows connection errors related to the Message Server. For example:

*** ERROR => MsIAttachEx: NiBufConnect to [Message Server hostname]/39xx failed (rc=NIECONN_PENDING) [msxxi.c      1521]
*** WARNING => Cannot connect to message server due to an error (rc=-100) [dpMessageSer 1912]
*** WARNING => DpMsAttach: failed to attach to Message Server (rc=-100) [dpMessageSer 1926]
***LOG Q0L=> DpLoopInit, nomscon () [dpInit.c     4071]
*** ERROR => DpTriggerMsAttach: Attach to Message Server failed [dpInit.c     4072]

• SAP NetWeaver ABAP based system
• ABAP Platform based system

Running but not connected to Message Server, Cannot connect to message server due to an error
NiBufConnect to [Message Server hostname]/39xx failed (rc=NIECONN_PENDING)  , KBA , BC-CST-STS , Startup Service , BC-CST , Client/Server Technology , Problem