3066827 - Error when opening an RFC connection (LB: Hostname or service of the message server unknown) in Business Workflow destinations

• When clicking Configure RFC Destination in the transaction code SWU3, it shows the below error for the WORKFLOW_LOCAL_* destination:
  
  Error when opening an RFC connection (LB: Hostname or service of the message server unknown#DEST =WORKFLOW_REFERENCE_)
  
  
• And when testing the RFC connections WORKFLOW_LOCAL_* and WORKFLOW_REFERENCE_* in the transaction SM59, the following errors can be seen:
  
  

  WORKFLOW_LOCAL_*

  Logon Connection Error
  Error Details Error when opening an RFC connection (LB: Hostname or service of the message server unknown DEST =WORKFLOW_LOCAL_* ).
  Error Details ERROR: partner 'hostabc:sapmsSID' not reached
  Error Details LOCATION: SAP-Server hostabc_SID_XX on host hostabc (wp X)
  Error Details DETAIL: NiPConnect2: 1.2.3.4:36XX
  Error Details CALL: connect
  Error Details COMPONENT: NI (network interface)
  Error Details COUNTER: 6929
  Error Details ERROR NUMBER: 10061
  Error Details ERROR TEXT: WSAECONNREFUSED: Connection refused
  Error Details MODULE: D:/depot/bas/777_REL/src/base/ni/nixxi.cpp
  Error Details LINE: 3485
  Error Details RETURN CODE: -10
  Error Details SUBRC: 0
  Error Details RELEASE: 777
  Error Details TIME: Sat Jun  5 18:40:11 2021
  Error Details VERSION: 40
  
  

  WORKFLOW_REFERENCE_*

  Logon Connection Error
  Error Details Error when opening an RFC connection (LB: Hostname or service of the message server unknown DEST =WORKFLOW_REFERENCE_).
  Error Details ERROR: partner 'hostabc:sapmsSID' not reached
  Error Details LOCATION: SAP-Server hostabc_SID_XX on host hostabc (wp X)
  Error Details DETAIL: NiPConnect2: 1.2.3.4:36XX
  Error Details CALL: connect
  Error Details COMPONENT: NI (network interface)
  Error Details COUNTER: 2809
  Error Details ERROR NUMBER: 10061
  Error Details ERROR TEXT: WSAECONNREFUSED: Connection refused
  Error Details MODULE: D:/depot/bas/777_REL/src/base/ni/nixxi.cpp
  Error Details LINE: 3485
  Error Details RETURN CODE: -10
  Error Details SUBRC: 0
  Error Details RELEASE: 777
  Error Details TIME: Sat Jun  5 18:43:12 2021
  Error Details VERSION: 40

• And the following entries can be seen in the corresponding RFC and work process trace files when the issue is occurring in the work directory (LocalDrive\usr\sap\<SID>\SCS<XX>\work):

  Name:         dev_rfcXX
  **** Trace file opened at 20210610 145512, by disp+work
  **** Versions SAP-REL 777,0,27 RFC-VER U 3 LATEST_CHANGE MT-SL
  Error RFCIO_ERROR_SYSERROR in D:/depot/bas/777_REL/src/krn/rfc/abrfcpic.c : 2968
  LB: Hostname or service of the message server unknown
  DEST =WORKFLOW_LOCAL_*
  MSHOST =hostabc
  R3NAME =SID
  GROUP =SPACE
  Destination: WORKFLOW_LOCAL_* (Handle: 2, DtConId: 00000000000000000000000000000000, DtConCnt: 0, ConvId: ,)
  EPP RootContextId: 00155D0A0C081EDBB2B9AFADA5B94429, ConnectionId: 00000000000000000000000000000000, ConnectionCnt: 0
  EPP TransactionId: B008A64529BB0020E0060067F2E2D8F0

  
  Name:         dev_wXX
  M Thu Jun 10 14:55:12 2021
  M  ***LOG Q0I=> NiPConnect2: 1.2.3.4:36XX: connect (10061: WSAECONNREFUSED: Connection refused) [D:/depot/bas/777_REL/src/base/ni/nixxi.cpp 3485]
  M  *** ERROR => NiPConnect2: SiPeekPendConn failed for hdl 54/sock 2904
      (SI_ECONN_REFUSE/10061; I4; ST; 1.2.3.4:36XX) [nixxi.cpp    3485]
  M  *** ERROR => MsIAttachEx: NiBufConnect to hostabc/sapmsSID failed (rc=NIECONN_REFUSED) [msxxi.c      1521]
  M  *** ERROR => LgIAttach: MsAttach (rc=MSENILAYER) [lgxx.c       5448]
  M  *** WARNING => LgIGroupRereadMs: LgIAttach(rc=-101) [lgxx.c       5604]
  A  TH VERBOSE LEVEL FULL
  A  ** RABAX: end RX_GET_MESSAGE

• SAP Business Workflow
• SAP NetWeaver
• SAP Web Application Server for SAP S/4 HANA
• ABAP PLATFORM - Application Server ABAP

WF_GDPR, SWF_WORKFLOW, WFMSTD, work directory, LocalDrive\usr\sap\<SID>\SCS<XX>\work, RFCIO_ERROR_SYSERROR, WORKFLOW_LOCAL_, Hostname or service of the message server unknown, 10061: WSAECONNREFUSED: Connection refused, NIECONN_REFUSED, MsIAttachEx, LgIAttach, rc=MSENILAYER, LgIGroupRereadMs, SWU3, SM59, RFC destination, NiPConnect2, RETURN CODE: -10 , KBA , BC-BMT-WFM , Business Workflow , BC-CST-LG , Logon group based load balancing , Problem