Testflight testers getting “unable to download app could not be installed at this time”

Question

I distributed version 1.0, build 1, of my app via TestFlight, and everything worked perfectly.

Yesterday I archived and sent out build 2, and now upon tapping the upd

Answer 1

We had a user who had, for reasons only they know, disabled cellular access for the Testflight app. Later, when he'd also turned off Wifi (again, for reasons...) he was in a situation where Testflight had no connectivity.

The error he saw was "could not load apps". It was driving us crazy as our other users were able to install and run without issue!