I recently ported an Android Maui app to iOS. I've got a loaner iPhone and I plugged it into the Mac I have for development and installed it using the installer program that runs on the Mac. It all worked great.
When I tried to put it on the client's phone, it went up with a little cloud symbol in the corner of the icon. I didn't know what this was, so I looked it up and it means it was offloaded (!!!!). It wouldn't run and I had no idea at the time why it would do that. Tried it again on an associate's phone. Same problem. We wondered if versions had anything to do with it. The device that it worked on was iOS 12. The other two were 15 and 16 (if I recall from the meeting).
I have been googling for an answer and coming up empty handed. Anyone know what's going on here?
To install developer builds on an iOS device, the device must be registered to your developer account and included in the provisioning profile that is embedded in the IPA file.
If you connect a new iOS device to your Mac while running Xcode and have "automatic signing" enabled, it will handle all of this for you.
If you produced an IPA file from Xcode without having connected these other devices and simply copied it to them, then their UDID's won't be included in the embedded provisioning profile and the app won't run.
You can also get the device UDIDs, manually add them to your developer account and include them in the provisioning profile for your app.
You may also want to look into TestFlight to provide a much simpler way of distributing test builds.