IMO, this is not a credentials issue. Things aren’t getting that far. ‘Connection refused’ is a network level error in which the host is being contacted but it is responding with connection refused either because “nothing listening on that port” or “you’re not allowed to access that port.”
Is a firewall in play?
What is the port number? If <1024 there may be issues (depending on the specific OS and setup).
Did the client (the remote partner) change the IP of the host perhaps? When was the last time your IS was restarted? The default behavior for the JVM is to cache host name lookups forever. If they changed the IP (moved their WS to another IP but still using the original hostname) then your IS will not connect to the new IP until it is restarted. Or change the config to use the IP instead of the host name.
Hopefully one of these resolves things or results in a new clue.
#webMethods#API-Management#soa