Symptoms

You are trying to create an application link and you input a server base URL i.e. http://myserver.mydomain.net:8090/confluence

But whenever you specify the URL, it is converted or changed to i.e. http://myserver:8090/confluence

Cause

Confluence base URL is configured differently as compared to the URL you use to access Confluence from the browser. In this case (as per example above) Confluence base URL is configured as http://myserver:8090/confluence instead of http://myserver.mydomain.net:8090/confluence

Resolution

Ensure that the URL you use to access Confluence from the browser matches the base URL configured in Confluence Admin > General Configuration and reconfigure the application link again.