Why the ERROR:root:Connection unexpectedly closed: [Errno 104] Connection reset by peer while sending mail?

[izzie123]

Hello,

We have an alert which is configured to send emails to users through an SMTP server. We notice that yesterday that particular alert created 63 events and while others successfully sent emails, there was an error while sending one alert.

ERROR:root:Connection unexpectedly closed: [Errno 104] Connection reset by peer while sending mail to "XXX@domain.com"

We are not sure if this is related to Splunk or should we check this on the SMTP server side. Can someone please guide?

This error occurred only once. The email flow was restored after a while.

Regards.

[PickleRick]

I'd definitely check the other end. It was either a network issue or deliberate connection closing by the server.