An unknown error has occured, AWS Amplify Login + React Native (Expo)

I'm configuring an application developed with React Native (Expo) to use the authentication process made available by Amplify. This is not the first time I have done this, I have initialized and deployed the authentication mode and through the Amplify CLI I have integrated it of the application. I can correctly register a new user to see him in Amplify Studio but when he tries to log in I get "An unknown error has occured."