I have installed the add-in in Word, but when trying to use it, it asks to update and then an error appears:

"We couldn't update this app.
Please contact your IT administrator for assistance."

Try fixing it by reinstalling the add-in from within Word:

• On the top ribbon: Click on the Home tab.
• At the far right of the ribbon, you will see a button that says Add-ins (it usually has an icon of a small square with a plus sign):
  
• In the search box: Type Writefull in the search bar. The Writefull icon should appear:
  
• To install, simply click on the icon. The add-in should appear to the right of the document in Word.