Office 365 received the message that you specified. Unfortunately, we couldn't deliver the message to the recipient ({0}) ...

Office 365 received the message that you specified. Unfortunately, we couldn't deliver the message to the recipient ({0}) because the service can't connect to the recipient email server. We kept trying to send the message for 48 hours, but finally gave up. We sent an email (non-delivery report) to the sender that gives the details about why the message couldn't be delivered.