Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi!
Since you changed your password, you need to disconnect and reconnect your Gmail account in Outlook. You mentioned that you cannot log in via the browser (OAuth), so the browser you are using might be blocking the login as well.
Which browser do you use? I recommend disconnecting and reconnecting the account in the browser first to update the access credentials.
Then try logging in again using the browser.