[ Google login works on localhost and test server, but not azure website (app service) ]

I am having a problem with signing in users with google on an Azure website using OWIN. Everything works fine localhost and on our test server, but when I deploy to our Azure website, the login fails.

I am using web api and OWIN to handle the authentication, and I have narrowed it down to this "simple" problem:

await AuthenticationManager.GetExternalLoginInfoAsync(); 

is returning null when deployed to azure.

• I have checked and double-checked the return url in the google api manager.
• I have tried setting a dummy session and clearing sessions as mentioned here: OWIN OpenID provider - GetExternalLoginInfo() returns null
• I write Googles clientID and clientSecret out in a log, so I know they are correct

Has anyone had similar problems when deploying to azure?

UPDATE:

Here is the code flow: First we hit the event "OnAuthenticated" on our google provider in Startup.Auth.cs when a user is logging in:

public void ConfigureAuth(IAppBuilder app)
{
    app.CreatePerOwinContext(ApplicationDbContext.Create);
    app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);
    app.CreatePerOwinContext<ApplicationSignInManager>(ApplicationSignInManager.Create);
    app.UseKentorOwinCookieSaver();
    var provider = new CookieAuthenticationProvider();
    var originalHandler = provider.OnApplyRedirect;
    app.UseCookieAuthentication(new CookieAuthenticationOptions
    {
        AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
        LoginPath = new PathString("/Login"),
        Provider = new CookieAuthenticationProvider
        {
            OnValidateIdentity = SecurityStampValidator.OnValidateIdentity<ApplicationUserManager, ApplicationUser>(
                validateInterval: TimeSpan.FromMinutes(30),
                regenerateIdentity: (manager, user) => user.GenerateUserIdentityAsync(manager)),
            OnApplyRedirect = context =>
            {
                if (!context.Request.Uri.LocalPath.StartsWith(VirtualPathUtility.ToAbsolute("~/api")))
                {
                    context.RedirectUri = new Uri(context.RedirectUri).PathAndQuery;
                    originalHandler.Invoke(context);

                }
            }
        }
    });
    app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);
    app.UseTwoFactorSignInCookie(DefaultAuthenticationTypes.TwoFactorCookie, TimeSpan.FromMinutes(5));
    app.UseTwoFactorRememberBrowserCookie(DefaultAuthenticationTypes.TwoFactorRememberBrowserCookie);

    var options = new GoogleOAuth2AuthenticationOptions
    {
        ClientId = System.Configuration.ConfigurationManager.AppSettings["googleServiceAccountWebApplicationClientId"],
        ClientSecret = System.Configuration.ConfigurationManager.AppSettings["googleServiceAccountWebApplicationClientSecret"],
        Provider = new GoogleOAuth2AuthenticationProvider
        {
            OnAuthenticated = context =>
            {
                //....
                return Task.FromResult(0);
            }
        },
        AccessType = "offline",
        SignInAsAuthenticationType = DefaultAuthenticationTypes.ExternalCookie
    };
    app.UseGoogleAuthentication(options);
}

After this event, we hit the method "ExternalLoginCallback" and the first thing we do is to call await AuthenticationManager.GetExternalLoginInfoAsync(); which returns null

[AllowAnonymous]
public async Task<ActionResult> ExternalLoginCallback(string returnUrl)
{
    var loginInfo = await AuthenticationManager.GetExternalLoginInfoAsync();
    //loginInfo is always null when published to Azure website
    if (loginInfo == null)
    {
        return RedirectToAction("NoAccess", "Login");
    }
    //....
}

Answer 1

I finally found the problem. It was an unhandled exception in the "OnAuthenticated" event. It took some time to find the problems, because this line:

HttpContext.Current.GetOwinContext().GetUserManager<ApplicationUserManager>();

Sometimes failed on azure. I changed alot of code to try and find/fix this problem, but I do believe it was an exception in OnAuthenticated.