Same issue is on our side. None of the testers received invite email. Will have to follow plan B - Firebase distribution.

TestFlight has been recovered at 4:19pm 04/14/23. Thanks Apple Team.

Processing is taking long today. 30 min has passed since upload and still build is being processed. In TestFlight tab - tapping on "build #" navigates to build's metadata page instead of build's test details page.