RPC server unavailable

I am facing with user login on a single site. When I try to login using my old id it works fine. There is no issue. But when I try to use some other id here I am getting a Server not found error. It is really weird. I had also created a entry in the host file and still it is not working. I am able to browse the site with old id. The new id that I am testing is created and configured well. After running ipconfig/registerdns I am getting "RPC Server unavailable" error.

There can be some problem with the security or permission stuff due to which your login fails to work. Do you have any more user ids. Try them and then see. If you are able to login then the issue lies with your new id.I am giving you a reference link of troubleshooting problem related to the error that you are getting. You can find more solutions here to fix the issue.

Troubleshooting "The RPC server is unavailable"