Email server name: {0} Email server IP address: {1} Connector name: {2} Technical error message: {3} Fix the problem Make ...

Email server name: {0}
Email server IP address: {1}
Connector name: {2}
Technical error message: {3}

Fix the problem
Make sure that the sever listed in the previous section is available. If your organization is using Microsoft Exchange, you can follow the steps in the following article: A Network Error Occurred while Communicating with Remote Host

We'll keep trying to send the message for a total of 48 hours. After that, Office 365 will stop trying to send the message and will return a non-delivery report (NDR) to the sender.