TestFlight users are saying the app won't install — what am I doing wrong?

Question

I'm new to TestFlight, and my users are running into issues with installing it, simply saying "Syllable could not be installed at this time."

I took the users' UDIDs, added them under my devices in the developer portal, then created a new Ad Hoc provisioning profile with those devices included. I then uploaded that new provisioning profile to TestFlight, then selected the users and clicked "Update and Notify".

In Xcode, I didn't change the debug code signing, but I changed the distribution to the Ad Hoc provisioning profile I created for TestFlight at the beginning. Do I need to update this for every new IPA I create/build I do? I'm thinking maybe this is being built using the old provisioning profile which doesn't have the new devices on it? I thought though just updating the provisioning profile on TestFlight's website would take care of this though.

Does anyone have any ideas what would be causing this?

Answer 1

So if I get this right,

if I upload a build, with the current provisionprofile, and then wants to add people (I recieve their UDID from testflight, add them to dev.apple- and to the provisionprofile),

and then I add the newly created provisionprofile with the new 5 persons to Testflight, update the Permissions-tab for the build and check so the newly added persons are current in the "checklist".

This wont be possible with the uploaded build, and they have to wait until next Build until they can install?