I set up my application for TestFlight. For external users it is waiting for review. But if I want to invite internal users, I select them and press invite. iTunes Connects says
Check your Trash/ Bin! All my 6 invites were automatically moved there because I unsubscribed from testing last week.
You have to fill the "What to Test" section. After you will be able to send invites for internal members.
only users with permissions can be added as Testers
steps to follow.
https://appstoreconnect.apple.com/WebObjects/iTunesConnect.woa/ra/ng/users_roles
https://appstoreconnect.apple.com/apps/1494800176/testflight/users
Internal Group
App Store Connect Users
A bit heavy-handed, but it works.
You're good to go.
For new builds on the same version, once the build becomes available, I had to turn OFF testing for that version and immediately turn it back on. This instantly sent an Update notification to TestFlightApp, emailed the testers, and allowed users install the new build.
This is an outstanding bug. A report has been filed, see details below. To get Apple to address this issue sooner, please submit a similar report through https://bugreport.apple.com