Power View Can't Load Power Pivot Models

Scenario: You have created an SSRS application in SharePoint and specified that the application pool would use a specific domain service account that is designated to SSRS. When you attempt to create a Power View report from a deployed Power Pivot model, you get the following error:

An error occurred while loading the model for the item or data source ''. Verify that the connection information is correct and that you have permissions to access the data source.