Hi,
I just received an email inviting me into the beta program. When I click the link in the final step (https://play.google.com/apps/testing/com.plexapp.android), I get the following:
App not available for this account
Your account isn’t currently eligible for this app’s testing program.
If you’ve been invited to become a tester, make sure that you’re signed in to the account that was invited to the testing program. If you’ve been invited to a Google Group or Google+ Community as part of the program, make sure that you’ve joined the Group or Community.