Mail - Native iOS Mail App

When I open the Mail app on my iPhone, I get a screen with the message: "No Message Selected" on a white screen. I have forced the app to close and restarted my iPhone. My software is also up to date (iOS 15.5). Notice also, from the screenshot that there's a blue button in the top right corner that says "Done" but it also doesn't work when I click on it.

Please tell me what I can do,