axis2 client, Transport error: 503 Error: Service Unavailable
We have a webservice client built using axis2 1.5.1 that we use to call webservice deployed on one of our vendor's web server (Server A). The client used to work fine untill recently when the vendor added another web server (Server B) for load-balancing purposes. Now, Server A and Server B both are hosting the same web-service that our ws client can issue requests to. The issue is that when the vendor's DNS entry is pointing to server B, we can issue requests to it and get successful responses back. When the DNS entry changes to point to Server A, our client can issue requests and get responses from it without problems. But again when the entry changes to point from Server A to Server B, we suddenly start receiving "Transport error: 503 Error: Service Unavailable" error messages from Server B. Our WS client is running in a multi-threaded environment and IP address changes are transparent to it since it uses domain name resolution to get to the web service. I took this issue up with the Vendor and they claim that everything is fine with both their servers (they are exactly identical) and that they receive nothing on their end at the time when I get the 503 error on my end. They suspect that the problem is with my client. I am unable to understand that this client code works perfectly when there is only one server (B) in question. It is also able to get responses when the webservice IP changes from B to A. But why does it start receiving 503s when the webservice IP changes back from A to B. I would appreciate any responses that can help me troubleshoot this issue. .