Issue with login when username has 'special symbols' (e.g. numbers etc.)

Widgets & Design

I have a Fltuterflow app that has a login page initially. I notice that when I have a user trying to login with their email, the login happens when the username (email) is sth like [email protected] , but when it is let's say [email protected] the login fails, and I get the error along the lines:

warm-caverns-48629-92fab798385f.herokuapp.com/https://server.name.gg/a/m/v/e/login:1 
        
        
       Failed to load resource: the server responded with a status of 500 (Internal Server Error)Understand this error
dart_sdk.js:11994 Uncaught (in promise) DartError: Unexpected null value.
    at Object.throw_ [as throw] (dart_sdk.js:11994:11)
    at Object.nullCheck (dart_sdk.js:12343:30)
    at login_widget._LoginWidgetState.new.<anonymous> (login_widget.dart:528:67)
    at Generator.next (<anonymous>)
    at dart_sdk.js:47081:33
    at _RootZone.runUnary (dart_sdk.js:46938:59)
    at _FutureListener.thenAwait.handleValue (dart_sdk.js:42334:29)
    at handleValueCallback (dart_sdk.js:42938:49)
    at _Future._propagateToListeners (dart_sdk.js:42976:17)
    at [_completeWithValue] (dart_sdk.js:42817:23)
    at async._AsyncCallbackEntry.new.callback (dart_sdk.js:42851:35)
    at Object._microtaskLoop (dart_sdk.js:47394:13)
    at _startMicrotaskLoop (dart_sdk.js:47400:13)
    at dart_sdk.js:43200:9Understand this error
25Chrome is moving towards a new experience that lets people make an informed choice with respect to third-party cookies.Understand this warning
index.ts:152 
        
        
       POST https://identitytoolkit.googleapis.com/v1/accounts:signInWithPassword?key=AIzaSyBiuwX3mhk-NMZVqW97CC-uMSbJ9RkNI90 400 (Bad Request)

Am I doing something wrong on the front end (Flutterflow) side or is there some issue in our back end implementation (Java)?

What have you tried so far?

Fixing it

Did you check FlutterFlow's Documentation for this topic?
Yes
1