Hi teams
We have encountered some errors. We are not sure where the problem lies.
KumoMTA internal: error in deliver_message: Error peer closed connection without sending TLS close_notify: https://docs.rs/rustls/latest/rustls/manual/_03_howto/index.html#unexpected-eof reading response to Some(DataDot)
kumod --version : kumod 2025.05.06-b29689af
That is not a KumoMTA issue, it’s just telling you that the other end of the connection didn’t follow the rules. Depending on the provider you may want to try lowering the number of messages you send per connection.
Every day during specific time periods, we send a large number of task emails to some internal corporate email accounts. We have also observed that, for the same email addresses, some are delivered normally while others experience errors such as timeouts. This could be a limitation on the recipient’s side, as you mentioned. It could also be because our Kumomta is using a new IP, whereas we never experienced this issue when using the original PowerMTA.
Or PowerMTA didn’t log cut connections?
Yesterday, we switched the sending domain to Kumomta; previously, we were using PowerMTA and were always able to send successfully. The difference is that Kumomta is using a new IP. PowerMTA did not show any abnormal errors.
Did PowerMTA log remote abrupt disconnects? Is there any other sign of issues beyond this error message?
PowerMTA has not log abrupt. other logs like ：failed to send message to copper-6->(mxbiz1|mxbiz2).qq.com@smtp_client Some(ResolvedAddress { name: "mxbiz1.qq.com.", addr: 183.47.104.46 }): Timed Out waiting 5s for response to Some(Rset)
Before this error occurred, there were records of the same email being successfully sent.
And you’re sending on a new IP?
And did you warm this IP?
This IP was not rigorously pre-warmed, but the volume of emails sent was not large, as they were all internal company emails. However, we may not have anticipated that there would be instances of sending 30-50 emails in a short period of time.