Problem with MAUI and Entra Login

Hi there

I have downloaded the PublicSingletonClient to use for logging into our Azure platform for a MAUI app that we rewrote from Xamarin.

The app was working fine, but all of a sudden I am having problems. It fails to interactively login if you are already logged in. It goes through the login process for silent, then goes to the interactive bit and fails. It gives different MAUI errors each time it fails, but it's the login that's failing. I don't know how to get around this problem and the app now doesn't work at all. I need help please.

public async Task<string> SignInUserAndAcquireAccessToken(string[] scopes)
{
    Exception<NullReferenceException>.ThrowOn(() => this.PublicClientApplication == null, PCANotInitializedExceptionMessage);

    var existingUser = await FetchSignedInUserFromCache().ConfigureAwait(false);

    try
    {
        // 1. Try to sign-in the previously signed-in account
        if (existingUser != null)
        {
                    
            this.AuthResult = await this.PublicClientApplication
                .AcquireTokenSilent(scopes, existingUser)
                .ExecuteAsync()
                .ConfigureAwait(false);
        }
        else
        {
            if (this.IsBrokerInitialized)
            {
                Console.WriteLine("No accounts found in the cache. Trying Window's default account.");

                this.AuthResult = await this.PublicClientApplication
                    .AcquireTokenSilent(scopes, Microsoft.Identity.Client.PublicClientApplication.OperatingSystemAccount)
                    .ExecuteAsync()
                    .ConfigureAwait(false);
            }
            else
            {
                this.AuthResult = await SignInUserInteractivelyAsync(scopes);
            }
        }
    }
    catch (MsalUiRequiredException ex)
    {
        // A MsalUiRequiredException happened on AcquireTokenSilentAsync. This indicates you need to call AcquireTokenInteractive to acquire a token interactively
        Debug.WriteLine($"MsalUiRequiredException: {ex.Message}");
        this.AuthResult = await this.SignInUserInteractivelyAsync(scopes);
    }
    catch (MsalException msalEx)
    {
        Debug.WriteLine($"Error Acquiring Token interactively:{Environment.NewLine}{msalEx}");
        throw msalEx;
    }

    return this.AuthResult.AccessToken;
}

        public async Task<AuthenticationResult> SignInUserInteractivelyAsync(string[] scopes, IAccount existingAccount = null)
        {
            Exception<NullReferenceException>.ThrowOn(() => this.PublicClientApplication == null, PCANotInitializedExceptionMessage);

            if (this.PublicClientApplication == null)
                throw new NullReferenceException();

            // If the operating system has UI
            if (this.PublicClientApplication.IsUserInteractive())
            {

                if (PublicClientSingleton.Instance.UseEmbedded)
                {
#if ANDROID
                    return await this.PublicClientApplication.AcquireTokenInteractive(scopes)
						.WithLoginHint(existingAccount?.Username ?? String.Empty)
						.WithUseEmbeddedWebView(true)
						.WithParentActivityOrWindow(Platform.CurrentActivity)
						.ExecuteAsync()
						.ConfigureAwait(false);
#else
					return await this.PublicClientApplication.AcquireTokenInteractive(scopes)
                        .WithLoginHint(existingAccount?.Username ?? String.Empty)
                        .WithUseEmbeddedWebView(true)
                        .WithParentActivityOrWindow(new MainPage(new TourGrosses.ViewModels.MainPageViewModel(new TourGrosses.Services.ApiService())))
                        .ExecuteAsync()
                        .ConfigureAwait(false);
#endif
                }
                else
                {
                    SystemWebViewOptions systemWebViewOptions = new SystemWebViewOptions();
#if IOS
                    // Hide the privacy prompt in iOS
                    systemWebViewOptions.iOSHidePrivacyPrompt = true;
#endif
                    return await this.PublicClientApplication.AcquireTokenInteractive(scopes)
                        .WithLoginHint(existingAccount?.Username ?? String.Empty)
                        .WithSystemWebViewOptions(systemWebViewOptions)
                        .WithParentActivityOrWindow(PlatformConfig.Instance.ParentWindow)
                        .ExecuteAsync()
                        .ConfigureAwait(false);
                }
            }

            // If the operating system does not have UI (e.g. SSH into Linux), you can fallback to device code, however this
            // flow will not satisfy the "device is managed" CA policy.
            return await this.PublicClientApplication.AcquireTokenWithDeviceCode(scopes, (dcr) =>
            {
                Console.WriteLine(dcr.Message);
                return Task.CompletedTask;
            }).ExecuteAsync().ConfigureAwait(false);
        }