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}). We couldn't deliver the message because the service can't connect to the recipient email server. After we tried to deliver the message for 48 hours, the message expired. We sent an email (non-delivery report) to the sender that gives the details about why the message couldn't be delivered.