If you are seeing this message when you invite another user to a collaboration you might wonder why. There are two reasons for why the person is picky with the invites:
1. Not part of the same group
In order to collaborate you will need to be part of the same group.
To check this, go to My Groups and click on a group to see if you find your collaborator in any of the groups. If you don't find your collaborator in any of your groups, a teacher will be able to add you to the same group.
2. Invite permission disabled
If you are part of the same group but still receive this message, it means that the owner has disabled collaborations for your collaborators role in Edu Admin > Permissions. Contact the Owner of the account to get more details.