TestFlight users can't download app "your request couldn't be completed"

Hi, my app was recently rejected by the App Store due to Invalid Provisioning Profile - the email contained this (and many, many more errors):

ITMS-90161: Invalid Provisioning Profile - The provisioning profile included in the bundle uk.ac.gla.timetable [UofG Life] is invalid. [Expired profile.] For more information, visit the iOS Developer Portal.

ITMS-90443: Invalid Provisioning Profile - The provisioning profile included in the bundle UofG Life [Payload/UofG Life.app] is invalid. [Expired code-signing certificate.] For more information, visit the iOS Developer Portal.

I went to the Developer Portal, went to Certificates/Identities/Profiles and saw the one for our app was marked 'Expired'. I went in to Edit it and renewed it there, at which point I could Download the profile.

I think I found advice to double-click it and it would fix the issue in Xcode. I was able to resubmit the app and Apple App Store accepted it so I thought the problem was fixed.

However, now none of the testers are able to get the app onto TestFlight, reporting the same issue, an error message saying "Could not install [app]. Your request couldn't be completed. Try again."

A lot of Xcode still mystifies me so I'm not really sure how to proceed here. Any Ideas would be appreciated!

I think I found the issue - I went to the Developer Portal again, got Distribution Certificate for my app and installed it on the MacBook. I built and distributed a new build and the tester reports they can download it now!

TestFlight users can't download app "your request couldn't be completed"
 
 
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