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.
Please see your admin if you need additional details.
It looks like the address that you typed isn't the right one for http://www.{0}. If you continue, people might not be able ...
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 ...