Gmail setup with Microsoft Outlook Desktop 

• Problem: Gmail user name & password is not working to add an additional email account to the Outlook desktop app.
• Solution:
  
  • Google security
  • Signing in Google > 2 Step Verification > Use App Password
  • Generate the new app password
  • Use this app password instead of Gmail password. 
• Tips
  • Enable the 2-step verification first
  • Then, select the app password