Link to app - https://play.google.com/store/apps/details?id=com.microsoft.office.outlook&hl=en_US&gl=US

1. Restart your phone. Hold down the power button until it gives you a prompt to restart.


2. Try resetting account in Outlook app 
  • Click the circle icon at the top left of the app
  • a window slides open, at the bottom left press the cog wheel icon
  • You should see your email address here under that "mail accounts" section, click on this.
  • scroll to the bottom of the screen and click on Reset Account, this will restart Outlook and make sure the app is working
3. Delete and re-add account
  • Click the circle icon at the top left of the app, then the gear icon at the bottom left again
  • Select your email address under mail accounts
  • Scroll down and click delete account.
  • Now click Add Account
  • It should already show accounts found, click continue. If not input your email address
  • lLgin with password and approve any 2 Factor if asked
4. Delete Outlook from phone, reinstall, and re-add account.

If issue still persist, please try resetting your email password and logging in again.