Hello Heather
I'm sorry to hear you are having trouble! The bounce messages that you see in bounce email events are generated by the recipient mail server or ISP and returned to us; they are not generated directly by us. In this case, it looks like the server is refusing connections by one of our IP addresses. Unfortunately, the message returned does not provide any more specific details than that as to why it is being refused. You will need to reach out to your IT team to see if they can provide more information about why this may be occurring.