AuthenticationManager.GetExternalLoginInfoAsync() on google aspnet mvc5 returns null
<p>I've developed an ASPNET MVC 5 application using default Visual Studio 2015 Template and Google authentication. All works fine in the development environment but on real the call after external authentication <code>AuthenticationManager.GetExternalLoginInfoAsync()</code> sometimes returns null. </p>

<p>Normally it returns null on the central hours of the day (from 08:00 to 20:00) but I haven't found a pattern because sometimes works at that time. I've watched the developer console, but there are not a lot of requests (22 in the last 12 hours) and all are successful.</p>

<p>I've tried some solutions from other StackOverflow threads but they didn't work. Also, I can try them only on the night because is a personal project and then the connection is successful and I can't reproduce the issue.</p>

<p>The code is standard:</p>

<ul>
<li><p>On Startup</p>

<pre><code>public void ConfigureAuth(IAppBuilder app)
{
    // Configure the db context, user manager and signin manager to use a single instance per request
    app.CreatePerOwinContext(ApplicationDbContext.Create);
    app.CreatePerOwinContext&lt;ApplicationUserManager&gt;(ApplicationUserManager.Create);
    app.CreatePerOwinContext&lt;ApplicationSignInManager&gt;(ApplicationSignInManager.Create);

    // Enable the application to use a cookie to store information for the signed in user
    // and to use a cookie to temporarily store information about a user logging in with a third party login provider
    // Configure the sign in cookie
    app.UseCookieAuthentication(new CookieAuthenticationOptions
    {
        AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
        LoginPath = new PathString("/Account/Login"),
        Provider = new CookieAuthenticationProvider
        {
            // Enables the application to validate the security stamp when the user logs in.
            // This is a security feature which is used when you change a password or add an external login to your account.  
            OnValidateIdentity = SecurityStampValidator.OnValidateIdentity&lt;ApplicationUserManager, ApplicationUser&gt;(
                validateInterval: TimeSpan.FromMinutes(30),
                regenerateIdentity: (manager, user) =&gt; user.GenerateUserIdentityAsync(manager))
        }
    });            
    app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);

    // Enables the application to temporarily store user information when they are verifying the second factor in the two-factor authentication process.
    app.UseTwoFactorSignInCookie(DefaultAuthenticationTypes.TwoFactorCookie, TimeSpan.FromMinutes(5));

    // Enables the application to remember the second login verification factor such as phone or email.
    // Once you check this option, your second step of verification during the login process will be remembered on the device where you logged in from.
    // This is similar to the RememberMe option when you log in.
    app.UseTwoFactorRememberBrowserCookie(DefaultAuthenticationTypes.TwoFactorRememberBrowserCookie);

    var google = new GoogleOAuth2AuthenticationOptions()
    {
        ClientId = "xxxx",
        ClientSecret = "xxxx",
        Provider = new GoogleOAuth2AuthenticationProvider()
    };
    google.Scope.Add("email");
    app.UseGoogleAuthentication(google);
}
</code></pre></li>
<li><p>On ExternalLoginCallback</p>

<pre><code>//
// GET: /Account/ExternalLoginCallback
[AllowAnonymous]
public async Task&lt;ActionResult&gt; ExternalLoginCallback(string returnUrl)
{
    Log.Debug("AuthenticationManager.GetExternalLoginInfoAsync()");
    var loginInfo = await AuthenticationManager.GetExternalLoginInfoAsync();
    if (loginInfo == null)
    {
        Log.Error("AuthenticationManager.GetExternalLoginInfoAsync(): null");
        return RedirectToAction("Login");
    }
...
</code></pre></li>
</ul>

<p><strong>More info</strong><br/>
I've created new Google credentials with another user and when I change the clientId and clientSecret, it works again... I don't know even when...</p>

<p><strong>Yet more info</strong><br/>
The problem is not on credentials, I "only" need to restart ASP.NET application to solve the issue, perhaps this new clue helps somebody to help me.</p>

<p><strong>Not replicated</strong><br/>
I've post the answer and it isn't in that <a href="https://stackoverflow.com/questions/19775321/owins-getexternallogininfoasync-always-returns-null">OWIN&#39;s GetExternalLoginInfoAsync Always Returns null</a> post, I've mentioned there the thread where I found the solution: <a href="https://stackoverflow.com/questions/20737578/asp-net-sessionid-owin-cookies-do-not-send-to-browser">ASP.NET_SessionId + OWIN Cookies do not send to browser</a></p>