It looks like the sender isn't a valid email address in your organization's address book. Check the email address for the Sender: {Sender}, and run the checks again.
If you entered the correct email address, you need to either create a mailbox for that user or create an external email address for them.
- In the Office 365 Admin center, go to the Active users page.
- Choose Add a user.
- Provide the requested information, and a mailbox is created automatically for the new user.
It looks like the recipient isn't a valid email address in your Office 365 address book, but it exists in your organization's ...
It looks like the recipient isn't a valid email address in your organization's address book. Check the email address for ...
It looks like the recipient isn't a valid email address in your organization's address book. Check the email address spelling ...
It looks like the recipient isn't a valid email address in your organization's address book. Please see your admin if you ...
It looks like the sender isn't a valid email address in your organization's address book. Check the email address for the ...
It looks like the sender isn't a valid email address in your organization's address book. Please see your admin if you need ...
It looks like this is a newsletter, but we aren\'t sure if it is safe to unsubscribe from it using the information provided ...
It looks like this person hasn't shared too much about themselves with Office 365 yet. Maybe next time you speak to them, ...
It looks like this user doesn't have a license to use Outlook with Office 365. Without a license, this user won't be able ...