Follow these steps and you're done:
- Clear your web browser's cache, cookies, history and then close browser. Open it newly. (This is just to ensure that all your log-in attempts are logged out completely)
- Go to outlook.com and try to login again.
Chrome
1. You can use the below link in Google Chrome to land directly in the settings
chrome://settings/clearBrowserData
2. Click CLEAR DATA.
3. Exit/quit all browser windows and re-open the browser.
Firefox
1. From the History menu, select Clear Recent History.
If the menu bar is hidden, press "Alt" to make it visible.
2.From the Time range to clear: drop-down menu, select the desired range; to clear your entire cache, select "Everything".
3. Next to "Details", click the down arrow to choose which elements of the history to clear; to clear your entire cache, select all items.
4. Click Clear Now.
5. Exit/quit all browser windows and re-open the browser.
Microsoft Edge
1. In the top right, click the Hub icon (looks like star with three horizontal lines).
2. Click the History icon (looks like a clock), and then select Clear all history.
3. Select Browsing history, then Cookies and saved website data, and then Cached data and files. Click Clear.
4. After the "All Clear!" message appears, exit/quit all browser windows and re-open the browser.