Looks like a combination of making the post "followers only" & tons of people refreshing our instance page caused the federation to misbehave quite badly. We are truly sorry about that.

To make it up to some of you, at 10:30PM CST (about 30 minutes from this post timestamp) we’re going to re-open spots in the same link (https://testflight.apple.com/join/S1BDT4Ab) as before on TestFlight. That way you can beat up Apple’s server instead of our own. Again, refresh the testflight link, not our server page. 😅