Explanation

This error can occur when you attempt to share with a user who does not have a @utoronto.ca email address that has been migrated into Office 365. ​ SharePoint Online relies on the email having been migrated into Office 365 in order to grant access.

Troubleshooting

When experiencing this issue, please take the recommended actions:

• If the user is with University of Toronto contact your local IT department for help. They may be able to tell you if the account has been migrated to Office 365.
• If you have invited someone outside of UofT (e.g. @gmail.com account) and receive this error message, it means External Sharing has been disabled for the site. This can only be enabled by EASI's Information Management team at request of the site administrator.

Related Resources

https://uthrprod.service-now.com/sp?id=kb_article&sys_id=05cfbc171b2ae0908d6e4118cc4bcbf0