The Plan Progression page gets displayed, but isn't loading any data for the selected Plan.
Generally this issue is caused because a Release hasn't been selected for the Plan being viewed.
In order for the Plan Progression page to load the information the Plan being displayed has to have a Release selected for its Start Release and End Release. You will need to go to the Capacity Planning page and select the Plan from there. If the Plan has been Published you will need to Edit it again. After that you can select the appropriate Releases for the the Start and End, and Publish the Plan.
Some other requirements for the Plan Progression page to work correctly are listed below: