Cannot debug on a remote server in NetBeans

I created a project to run in a remote server. The FTP connections is working; I can run a web application in the remote server and it access files in the server. When I debug, NetBeans doesn't stop at the break points. When I close the debug session, I don't get the error message that NetBeans cannot communicate with XDebug.

What am I missing?

Your help will be greatly appreciated