title: Why does https://login.microsoftonline.com/... login page shows GUID instead of user email?
body: <p>I am using Microsoft azure Active directory B2c to authenticate our website. we follow the model given <a href="https://docs.microsoft.com/en-gb/azure/active-directory/active-directory-devquickstarts-webapp-dotnet" rel="nofollow noreferrer">here</a> to authenticate our website. The authentication flow is as follows</p>
  
  <ol>
  <li>I click signin button(in our site) to login(login page redirects the user to microsoft online login page)</li>
  <li>I am redirected to microsoft login page <a href="https://login.microsoftonline.com/" rel="nofollow noreferrer">https://login.microsoftonline.com/</a> with all the custom values like tanent id, etc.</li>
  <li>I enter the user name and password to login.
  ......</li>
  <li>I click logout at the end, I am logged out of the site.</li>
  </ol>
  
  <p>Next time when I login, the flow is as follows</p>
  
  <ol>
  <li>I click login button(from our site)</li>
  <li>I am redirected to the microsoft login page.</li>
  <li>Microsoft Login page remebers my email as I already logged-in once</li>
  <li>I clicke my email</li>
  <li>I am redirected to a login page, where I enter username(email) and password</li>
  </ol>
  
  <p>It works fine most of the times. But sometimes microsoft login page shows GUID instead of my user email id on its login page. Is there a reason why the login page shows GUID instead of email and how to avoid this? Following is the screen short that shows GUID instead of email</p>
  
  <p><a href="https://i.stack.imgur.com/smTAd.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/smTAd.png" alt="enter image description here"></a>  </p>