[NotAuthorizedException: Token is not from a supported provider of this identity pool.] error when trying to use fetchUserAttributes and getAuthSession.

I am working with React native and AWS Amplify. Our website uses Amplify v5 whereas I am using Amplify v6 in the app, but used the same config file. SignIn, SignOut steps are working correctly along with getCurrentUser API from 'aws-amplify/auth' package. But fetchUserAttributes and fetchCurrentSession are giving ' [NotAuthorizedException: Token is not from a supported provider of this identity pool.] ' error. Our website as working on Amplify v5 uses Auth.currentAuthenticatedUser(), Auth.currentSession() which work perfectly fine. What is wrong here ? Any help