If Outlook won't allow you to send emails or is displaying a message that the program is unlicensed, this article will give you the step-by-step directions to resolve the issue.
Please use the following steps to restore the license for MS Office on your computer:
Close all of the MS Office programs
Sign-out of MS Office account
Open Word, but don't select a template
Click on "Switch Account"
Click on "SIGN OUT"
Then click on "Sign out" next to any accounts displayed
Sign back in to MS Office account
Click "Sign in to get the most out of Office"
Enter your email address and password on the next two screens
Click "Sign In"
confirm that it is no longer showing the unlicensed product notification and that it will allow you to send emails again.