Active Workspace is a web client for Teamcenter. When you connect to Teamcenter using Active Workspace, you will access a URL and port through the browser which connects you to this web application. The Active Workspace application then connects from the web application server to Teamcenter using the 4-tier URL and FMS URL. These 2 URLs are accessible from the server where the Active Workspace web app is running, but may not be accessible to your Mendix app.
If they are accessible, make sure you get the right port numbers when you configure your Teamcenter connection for the Mendix connector. The URLs and port numbers you use here are NOT the Active Workspace URL and port. Your Mendix app does not connect to Active Workspace: it connects to Teamcenter itself.