3507673 - Error ""Connection test failed" while trying to set up a new RFC connection - Tricentis

When the user trying to set up a new RFC connection in their ECC system then they might face the below error when they test the connection : 

""Connection test failed!

Error code = -304

Details: 

RFC error. rc=0. Description=Opening RFC connection. Key=RFC_COMMUNICATION_FAILURE. Message=
LOCATION    CPIC (TCP/IP) on local host with Unicode
ERROR       partner '158.113.21.112:3300' not reached
TIME        Wed Sep 30 15:23:09 2020
RELEASE     721
COMPONENT   NI (network interface)
VERSION     40
RC          -10
MODULE      nixxi.cpp
LINE        3289
DETAIL      NiPConnect2: 158.113.21.112:3300
SYSTEM CALL connect
ERRNO       10061
ERRNO TEXT  WSAECONNREFUSED: Connection refused
COUNTER     2""

SAP Change Impact Analysis by Tricentis

TOSCA, TTA, application server, connect, destination, SAP router , KBA , XX-PART-TRI-CIA , SAP Change Impact Analysis by Tricentis , Problem