title: Azure B2C. User account does not exist in tenant 'xxx' and cannot access application
body: <p>We get the following error when trying to access an AAD application, which is connected to Azure B2C.</p>
  
  <blockquote>
    <p>User account 'xxxxx@gmail.com' from identity provider 'live.com' does not exist in tenant 'xxxxxxxx' and cannot access the application 'xxxxxxxxxxx' in that tenant. The account needs to be added as an external user in the tenant first. Sign out and sign in again with a different Azure Active Directory user account.</p>
  </blockquote>
  
  <p>The live account shows up in both the B2C and AAD as a live.com user.  Manually created accounts can log in.  Yet when logging in from a B2C account, I get the above error.</p>
  
  <p>How can I solve this problem?</p>