Forum Discussion
Office 365 SharePoint Site Shared With External - Some users have "Deny" Permissions
Joe, you are able to share with an already accepted external user from a domain A on another externally shared site where domain A is not white listed is because the user from domain A is in your AAD and is a valid user in your tenant. Good thing is - though you can add the user to the site, the user gets notification but they will not be able to access the content on the site. When you check the user's permissions, you will see the deny list. When the user tries to access the link, he/she will be prompted with a message "Let us know why you need access...". Access request approving person on the site will be able to see requests and be able to approve but the user still gets "Let us know why you need access..." message.
But to your and our concern, the user shouldn't be allowed to receive share or invite notifications when their domain is not white listed on a site collection.
Hope this helps.