No TestFlight invite email gets sent for internal users

Question

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

Answer 1

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.