Outlook for Mac isn't accepting my password
You attempt to sign in to Outlook for Mac, and even though you've entered the correct password, Outlook for Mac doesn't accept it and continues to prompt you for your password. Here are two possible solutions:
Situation 1: Your macOS password was reset
If your macOS user account password was recently reset, it might not match the password of your login keychain. To fix this, see this article from Apple to create a new login keychain or update it with your new password.
Situation 2: Your mac was recently updated
If you've installed the most recent macOS update (released in December 2016), Outlook for Mac might stop accepting your password, which used to work just fine. To fix this, repair the Outlook client configuration files that were corrupted.
- Quit Outlook for Mac.
- In your Applications folder, find and open Keychain Access. It may be in the Utilities folder.
- On the left sidebar, under Keychains, select login.
- Under Category, select All Items.
- In the upper-right, search Exchange.
- Select all the results, right-click (or two-finger click), and select Delete (all) items.
- Repeat steps 5 and 6, searching for Office, making sure to delete all the results.
- Repeat steps 5 and 6 again, searching for ADAL, making sure to delete all the results.
- Open Outlook for Mac.
- Enter your password in the prompt, and complete 2-factor authentication if asked.
- If Outlook still won't accept your password, create a new macOS user, and try to use Outlook with that profile instead.