Clear up Credentials in Web Browser

This route will force the applications to request the user credentials before opening it up. 

Step-by-step guide

  1. Click on the Windows button and type "credentials".

  2. Select Credential Manager. 

  3. Go to Windows Credentials.
  4. For all of the Microsoftoffice16, click the drop down and select remove. 

  5. Do the same for all the Microsoft office16. 

  6. Go back and relaunch Skype for Business and Outlook.