It looks like the recipient isn't a valid email address in your Office 365 address book, but it exists in your organization's on-premises mail server. To fix this problem for the Recipient: {Recipient}, you need to add the external email address to Office 365.
- In the Exchange admin center, go to the Contacts page.
- Choose New (Add icon), choose Mail contact.
- Complete the required fields in the new mail contact page.
It looks like the CSV file has too many columns. Check the column headings to make sure they match the column headings in ...
It looks like the IP address that you typed isn't the right one for http://www.{0}. If you continue, people might not be ...
It looks like the recipient ({0}) 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 Office 365 address book, but it exists in your organization's ...
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 ...