quickbooks app 2021

Hi there, since a last update of eitherickBooks my app doesn’t no longer load or work. I hit the button on my Home Screen I get a white screen with QuickBooks logo for about a second and then it just goes back to my home phone screen. I am running 14.4 software on phone. I have tried turning phone off and on, deleting app and turning phone off and on and reinstalling app from App Store. I’ve spoke to customer service (what service) at QuickBooks who say it’s not there problem, there’s nothing wrong at their end must be a incompatible problem with the device. It’s been 9 days since I discovered the problem, so I am hoping someone here may be able to help. Thank you.