Apple Mail app deleted - reinstalled app won't work

My Apple Mail app was deleted by one of my children! I downloaded the app again and opened it expecting my emails to appear. What actually happens is the "Welcome to Mail" window appears, so I click on "iCloud" and it asks for my email address, which I put in, then click "next" and it asks for my password, which I put in and click "next" and it says it's verifying and the wheel spins but then the wheel stops and disappears but nothing has happened. If I click "next" again it just repeats the same thing no matter how many times I try, so the only option is to cancel.

Can anyone tell me what am I doing wrong please. It's and iPhone 8 plus running iOS 16.5.