To repair an Outlook Account for Outlook 365, please follow these steps.
Step One: Open Outlook, click the File tab.
Step Two: click the down-arrow next to "Account Settings", and then "Account Settings..."
Step Three: on the Email tab, select your account (profile), and then click "Repair".
Be sure to follow the prompts in the wizard and once done, restart Outlook.
If Outlook is not running...
Click Start -> Control Panel -> Mail (32-bit) or just Mail (you can see these options with the "View By" set to Large).
Select E-mail Accounts from the new window.
Next, on the Email tab, select your account (profile), and then click "Repair".
Be sure to follow the prompts in the wizard.