Unable to Properly Download United Airlines App on new iPad with IOS15

When I try to download the United Airlines App from the App Store, the icon appears on my home screen, but when I press it, it briefly opens and closes again. I have tried to install this more than 10 times. I have also re-booted the iPad and then try to install again. Same results. The app is not appearing in my app list in settings and I don't get any results when I search for it.. I have called United Airlines tech support and they said it must be a problem with the iPad. It is installed properly on my iPhone and worked perfectly fine on my old (9 years old) iPad. The app did not work on the software that came with the iPad (14) and does not work on the newly installed iOS 15.1.