OpenIdConnect error. Tenant IDs may not be a blank GUID

I am trying to use OWIN Open ID Connect middleware to outsource authentication for my ASP.NET application to Azure Active Directory. The app successfully redirects to the Azure AD sign-in page when accessing a page that requires authorization. However, when logging into Azure AD, I encountered the following error:

AADSTS90002: The requested tenant ID '00000000-0000-0000-0000-000000000000' is not valid. Tenant IDs may not be a blank GUID.

Here's the challenge UseOpenIdConnectAuthentication

. The tenant who is included in the Authority's URL is f82d0e29-6018-43c6-b806-1f46a009ff4a. So why does Azure AD think that I am passing in an empty GUID for the tenant?

app.UseOpenIdConnectAuthentication(new OpenIdConnectAuthenticationOptions
            {
                AuthenticationType = "AzureAd",
                Caption = "Office 365",
                Scope = "openid email profile",
                ClientId = "e34401b2-6a9f-4547-9229-f0d93a33b1a1",
                Authority = "https://login.windows.net/f82d0e29-6018-43c6-b806-1f46a009ff4a/",
                PostLogoutRedirectUri = "http://localhost:44333",
                RedirectUri = "http://localhost:44333",
                AuthenticationMode = AuthenticationMode.Passive,
                SignInAsAuthenticationType = signInAsType
            });