Can't add build to test for Internal tester

Question

I can't add processed builds for Internal testing. But it's available for external testing though. This is strange. Any ideas on this?

Internal testing

External testing

Answer 1

As it turned out, i changed the version of the app to 0.1 (previously it was 1.0). And uploaded a new build to the TestFlight. and it worked this time.

But, still issue with version 1.0 though.