You can enter a user’s email address and see the list of published apps in your environment and all the access, license, and security information specific to that user. This can be very useful in troubleshooting why a user cannot see a specific app in your environment. The tool can be accessed from the admin center or via direct URL.
https://<org>.crm.dynamics.com/WebResources/msdyn_AppAccessChecker.html
Hope this helps..
nijos.dev 