<user@166.131.9.213>: connect to 166.131.9.213: Connection timed out
A "connection refused," or "connection timed out" message usually results from high volumes of mail being processed at the time your message was received. This could be due to the server receiving more mail then it is used to, a external attack on a domain (such as a mailbomb) or an internal setup problem, causing the domain's mail servers to refuse connections or cut connections before a message is fully sent. Mail exchangers are set up to only accept as much mail as they can handle, so when problem is resolved, you will be able to send your mail without problem.