Outlook SMTP Oauth2 error

Outlook’s SMTP server currently has an issue with Oauth2. It may be temporary but it has already lasted several days at this point. It should be fixed by Outlook eventually, but to fix this immediately, you can switch POP Peeper to use the password method instead of Oauth2:

  1. Edit the account in POP Peeper
  2. To the right of your “Login name”, change the selection to “Password”
  3. Make sure that you have the correct password entered
  4. Press “Update” to save and then you should be able to send any queued messages (press “Check Mail”)