I've just put a Bêta APK of my app on the Developer Console. I've also created a Google Group and invited the people that can download the Bêta version of the app.
Google gives you a link in this format :
https://play.google.com/apps/testing/com.app.package
Normally you would give this link to the testers, and if they actually exist in the Google Group they can open it and click the button Become a Tester
and would be able to download the bêta version of the app directly from Google Play.
The problem is that some contacts, even though they actually exist in the group and can click on the button Become a Tester
... they can't get to the page where they can download the app. A message is displayed saying :
Not Found
We're sorry, the requested URL was not found on this server.
Some users can download the app and others can't, even if they exist all in the same Google Group. Does anybody have any idea ?