I'm currently working on an iMessage Sticker Pack but there seems to be an issue with TestFlight in iTunes Connect. In the "All Builds" section it shows that the build is Ready for Testing but also displays a grey icon next to it. However, when I proceed to add the build in the External Testing Section the process gets stuck on the last screen.
What does the grey icon mean?
Did you find a solution for this? I am having a similar problem, old build shows a gray icons... new builds keep disappearing from the list
You should have a close look at the Signing certificates. The problem with my build was that the the signing certificate for the extension was a developer certificate, while for the app target it was a distribution certificate. This is what created the issue in my case.
