Only white screen on opening

I created an app
I downloaded more than one version on my personal phone to test the design
I didn’t add anything else but the design
The app worked perfectly
But two days ago, when I downloaded the latest version, only a white screen has appeared, and there was nothing else
I changed almost everything to find out why and there was no result unfortunately
I even hide all the content of the pages and kept one test page and there was no result either
I want help, please

Build 353643: SINBAD

FYI, i am just a beginner