The QR Code sharing feature may sometimes become unavailable. Microsoft OneDrive and OneDrive for Business may occasionally invalidate tokens for security reasons. This is most likely to occur when users request password resets, application token resets, etc. for the affected account. 

If this occurs,  perform the following steps: 

1.  Sign-in to https://myViewBoard.com.
2.  Go to the Cloud Integration page. 
3.  Rebind all affected OneDrive accounts.

Note that this is a common and standard practice, and takes place within the Microsoft Office 365 framework with no notice or warnings to third parties such as myViewBoard.

For more information about the QR Code sharing feature, see the following page:

https://wiki.myviewboard.com/File_Management