How do I redirect users to the login page when a session has timed out in Blazor?

Create a RedirectLogin component to redirect users to a login page when their session has expired.
RedirectLogin.razor]
@inject NavigationManager UriHelper
 
@code {
    [CascadingParameter]
    public Task<AuthenticationState> StateAuthenticate { get; set; }
 
    protected override async Task OnInitializedAsync()
    {
        var authenticationState = await StateAuthenticate;
        if (authenticationState?.User?.Identity is null || !authenticationState.User.Identity.IsAuthenticated)
        {
            var returnUri = UriHelper.ToBaseRelativePath(UriHelper.Uri);
            if (string.IsNullOrWhiteSpace(returnUri))
            {
                UriHelper.NavigateTo("YourLoginPath", true);
            }
            else
            {
                UriHelper.NavigateTo($"YourLoginPath?returnUrl={returnUri}", true);
            }
        }
    }
}

Now, initialize the RedirectLogin component in App.razor to identify whether a session is expired or valid.
[App.razor]
<Router AppAssembly="@typeof(Program).Assembly">
        <Found Context="routeData">
            <AuthorizeRouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)">
                <NotAuthorized>
                    <RedirectLogin />
                </NotAuthorized>
                // . . .
            </AuthorizeRouteView>
        </Found>
        // . . .
    </Router>