During the installation of the app iOS just prints that it can’t install the app.
The best solution is to check the device’s iOS device logs, as described in this guide: https://developer.apple.com/library/content/technotes/tn2319/_index.html (specifically this section: https://developer.apple.com/library/content/technotes/tn2319/_index.html#//apple_ref/doc/uid/DTS40013778-CH1-TPRO )
Most frequent issues are code signing related, but in any case the iOS device log should include the error why it rejects to install the app.