3688893 - “ERRNO TEXT Connection reset by peer” when checking an RFC connection in SAP Cloud Connector

Cloud connector and message server on different networks.

When performing an availability check for an RFC connection in SCC mapping you can see host is not reachable and receive error message where you can see information below:

ERROR connection to partner '<host>:36xx' broken

ERRNO 104

ERRNO TEXT Connection reset by peer

The following error message can be found in scc_core.trc: 

2025-09-22 10:25:18,784 +1300#INFO#com.sap.scc.rt#AccessControl connection checker#          #SccEndpointValidator connection to RFC://<host>:36XX as direct abap application server failed. Maybe host/port is pointing to an ABAP message server.
com.sap.scc.jni.CpicCommunicationException: 
LOCATION    CPIC (TCP/IP) on local host
ERROR       connection to partner '172.XX.XXX.XXX:36XX' broken
TIME        Fri Sep 22 10:25:18 2025
RELEASE     754
COMPONENT   NI (network interface)
VERSION     40
RC          -6
MODULE      /bas/754_REL/XXX/XXX/XX/
LINE       3432
DETAIL      NiIRead: P=172.XX.XXX.XX:36XX; L=192.XXX.X.XX:XXXXX
SYSTEM CALL GwRead
ERRNO       104
ERRNO TEXT  Connection reset by peer
COUNTER     8

SAP Cloud Connector

RFC, reset, peer, errno, errno 104, mapping, test connection, check availability, traces, scc, cloud connector, router, network , KBA , BC-MID-SCC , SAP Cloud Connector On-Demand/On-Premise Connectivity , Problem