The error message might look like this:
org.apache.axis2.AxisFault: Transport error: 403 Error: Forbidden at org.apache.axis2.transport.http.HTTPSender.handleResponse(HTTPSender.java:310)
This can occur when you are using a non-whitelisted IP address. Please check if your IP address you are using for the outgoing connection was provided to Hubject through the Hubject ticket system found in step "Whitelisting of the IP Addresses". Please check if you have received a confirmation for this ticket regarding the whitelisting process.
Check CPO: Whitelisting of the IP Addresses
Check EMP: Whitelisting of the IP Addresses