Hi again, @ETNyx
We have now re-enabled SOGo to double-check the behavior. We set the exact same autoresponder message both in Mailcow’s admin panel (Sieve filter) and in SOGo. Unfortunately, the result is the same — the autoresponder messages are still not delivered to Gmail.
This strongly suggests they are still not passing through Postfix, and therefore are not DKIM-signed or SPF/DMARC-compliant.
What’s more — we tested the same scenario using a non-Gmail sender address, and in that case the behavior is completely correct: the autoresponder message is delivered successfully and does not end up in spam. This makes the Gmail delivery issue even more clearly related to missing DKIM/SPF alignment.
From what we can tell, this means the issue is not limited to Mailcow admin–configured Sieve filters, but also applies to SOGo’s vacation messages in our setup.
Option 1. Mailcow admin panel:
require ["fileinto", "vacation", "copy"];
# Move spam to spam folder
if header :contains "X-Spam-Flag" "YES" {
fileinto "spam";
# Stop here so that we do not reply on spams
stop;
}
vacation
# Reply at most once a day to a same sender
#:days 1
:subject "Automatyczna odpowiedź"
:addresses ["*"]
:mime "MIME-Version: 1.0
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 7bit
<!DOCTYPE html>
<html>
<head>
<meta charset=\"utf-8\">
<meta name=\"viewport\" content=\"width=device-width\">
<meta http-equiv=\"X-UA-Compatible\" content=\"IE=edge\">
<meta name=\"x-apple-disable-message-reformatting\">
</head>
<body width=\"100%\" style=\"font-size:0.9em;font-family:Calibri,sans-serif;color:#3d3c3f;\">
<p>I hereby inform you that I have terminated my employment with XYZ on July 31, 2025.</p>
<p>Your message has been forwarded to the appropriate department.</p>
</body>
</html>";
Option 2. SOGo
Could you confirm if, in a standard Mailcow + SOGo setup, vacation messages are expected to go through Postfix for signing? Or is there a known configuration tweak to ensure this path?
Thanks!
