If a student is trying to submit in Canvas, but when they click on Office365 to find a document the box is blank, then perform the steps below to fix it.
How to fix a blank Office365 tab:
Click Account on left and then Settings
If a pop-up window appears, click the Leave button
Scroll down to the Approved Integration section and find the Office365 Prod lad section. Click the trash icon to the right of that area.
Click OK and go back and the Office365 tab should no longer be blank.