Thank you, evsxez1, it helps people from Belarus as well. And after a whole day of fighting this problem when I was double checking and rechecking all variants I connected to the USA server (VPN) and voila(!) it worked! (The small remark: I had no problems on my first iPhone SE, successful installs all the time without VPN, same ipa, same profile) I made some other checks and I'm sure that my problem was definetely related to this. Finland server didn't help and I decided that this is not a problem with network. You should now be able to launch the Instagram++ app without the system complaining of its authenticity. Tap on Trust and then Trust again to make sure that the iOS platform trusts the app to allow it to launch.

Then I read the comment above, I've already tried to perform install via VPN but via Finland servers (as I'm from Russia and that could be a problem). Step 4: Find the profile that’s assigned to the installed application and tap on it. Updated Mac OS + XCode 13.3.1 to latest versions (because I had one iPhone SE that gets install without problems, iOS version 14.8.1 and supported SDK in my previous XCode version 12.2 and another iPhone XS iOS 15.3.1 with a problem). 8 hours of frustration and different attemtps. ipa AdHoc via Firebase App Distribution, all UDID are ok, all provisioning profiles too, result: 'Unable to install MYAPP Please try again'.

Zero to One for ios instal free