Understand whey Ironport ISQ classifies as Suspected Spam

[EU-GDPR-CITIZEN]

When experiencing sending issues, as Step 1, a number of well-known RBL DNSBL reputation sites are used to confirm that we have not become listed or otherwise seen a sudden drop in reputation.

An organisation reported an email from us as being received tagged [SUSPECTED SPAM].  I have omitted sensitive details but can disclose the email with full headers.  What is the reason this was tagged in this way please?

From: <me>
To: <recipients>
Message-ID: <uuid@our-domain>
MIME-Version: 1.0
Content-Type: multipart/mixed;
 boundary="----=_NextPart_000_00DB_01D7D491.078F57A0"
X-Mailer: Microsoft Outlook 16.0
Thread-Index: AQHXw/FvU0ep0dyzFEehDfDdQsYyCw==
X-MS-Exchange-Organization-AuthSource: <their-hostname>
X-MS-Exchange-Organization-Network-Message-Id: <uuid>
Content-Language: en-us
x-ms-exchange-transport-endtoendlatency: 00:00:00.3035261
x-ms-exchange-processed-by-bccfoldering: 15.01.2308.015
X-MS-Exchange-Organization-AuthAs: Anonymous
X-MS-Exchange-Organization-AVStamp-Enterprise: 1.0
Authentication-Results: <their-hostname>; dkim=none (message not signed) header.i=none; spf=Pass smtp.mailfrom=<me>
X-Ironport-Dmarc-Check-Result: validskip
X-DEBUG: LISTENER-MTA-incoming
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: =?us-ascii?q?A0FVRgCblGlh/0LCX1BRBgMaAQEBAQE?=
 =?us-ascii?q?BAQEBAQMBAQEBEgEBAQECAgEBAQFJgVCBIYEBB0wrLCoBKAMHCDEChEaDSoU?=
 =?us-ascii?q?5hWmCJAM4AZt7gREGUQQLCQkzBgEBAgQBAQECAQKBMYIuRVSCSwIlATgTAQI?=
 =?us-ascii?q?EAQEBEgEBAQQBAQECAQMDAgEBAQECgQ0ThWgNgjUpAXSBBwEBAQEBAQEBAQE?=
 =?us-ascii?q?BAQEBAQEBAQEBFgIlUgxCAQMBJTECIxsVAiEBAgQDAgQ3DQkOAQwGAgKCbQG?=
 =?us-ascii?q?CdxQBCqwVeoExH2I7glo9A4RAToEFEIE6AYFThUQBgniDfTeBVUSBPAwDgj0?=
 =?us-ascii?q?HMD5rGgFNgRADARhDAUgFAQgCAQcBAzUKJoJRgkMiBItUET0oDBIGGwExASo?=
 =?us-ascii?q?LEQ4BAx8PHzsCDEIOHDkRkVoGUYxNgT6BeIlgkXgzB4M0gTIGC4QDhQGLHIV?=
 =?us-ascii?q?5gwAGFCyDaoFIiiWXQSwXhjmPDB+MUJNCVQEBfGuFISVpVRQHMxo0P2QBAYI?=
 =?us-ascii?q?DCUgZD443IIEVhn+DIYJlQAMwAgQyAgYLAQEDCYVHAQGLEQICDRcHghcBAQ?=
X-IPAS-Result: =?us-ascii?q?A0FVRgCblGlh/0LCX1BRBgMaAQEBAQEBAQEBAQMBAQEBE?=
 =?us-ascii?q?gEBAQECAgEBAQFJgVCBIYEBB0wrLCoBKAMHCDEChEaDSoU5hWmCJAM4AZt7g?=
 =?us-ascii?q?REGUQQLCQkzBgEBAgQBAQECAQKBMYIuRVSCSwIlATgTAQIEAQEBEgEBAQQBA?=
 =?us-ascii?q?QECAQMDAgEBAQECgQ0ThWgNgjUpAXSBBwEBAQEBAQEBAQEBAQEBAQEBAQEBF?=
 =?us-ascii?q?gIlUgxCAQMBJTECIxsVAiEBAgQDAgQ3DQkOAQwGAgKCbQGCdxQBCqwVeoExH?=
 =?us-ascii?q?2I7glo9A4RAToEFEIE6AYFThUQBgniDfTeBVUSBPAwDgj0HMD5rGgFNgRADA?=
 =?us-ascii?q?RhDAUgFAQgCAQcBAzUKJoJRgkMiBItUET0oDBIGGwExASoLEQ4BAx8PHzsCD?=
 =?us-ascii?q?EIOHDkRkVoGUYxNgT6BeIlgkXgzB4M0gTIGC4QDhQGLHIV5gwAGFCyDaoFIi?=
 =?us-ascii?q?iWXQSwXhjmPDB+MUJNCVQEBfGuFISVpVRQHMxo0P2QBAYIDCUgZD443IIEVh?=
 =?us-ascii?q?n+DIYJlQAMwAgQyAgYLAQEDCYVHAQGLEQICDRcHghcBAQ?=
X-IronPort-AV: E=Sophos;i="5.85,376,1624320000"; 
   d="pgp'?scan'208,217";a="184292691"
X-Amp-Result: UNKNOWN
X-Amp-Original-Verdict: FILE UNKNOWN
X-SW-MTA-ORIGIN: INTERNET
X-SW-MTA-Node: <their-hostname>
X-SW-MTA-EnvelopeFrom: <me>
X-SW-MTA-HAT-Group: UNKNOWNLIST
X-SW-MTA-MailflowPolicy: $ACCEPTED
X-SW-MTA-MessageID: 184292691
X-SW-MTA-FROM: <me>
X-SW-MTA-URLORATTACH: 
X-IronPort-Outbreak-Status: No, level 0, Unknown - Unknown
Disposition-Notification-To: <me>

This is a multipart message in MIME format.

------=_NextPart_000_00DB_01D7D491.078F57A0
Content-Type: multipart/alternative;
	boundary="----=_NextPart_001_00DC_01D7D491.078F57A0"

What in that identifies what it concluded and why it attached a [SUSPECTED SPAM] tag.

BTW, regarding the X-Mailer header, that was NOT set by use in the outbound mail.

TIA.

[Udupi Krishna.]

Hard to say. Open a TAC case and provide them the email sample which has these headers intact, specifically "X-IPAS-Result" which will be decoded by Cisco/TALOS. Common reasons would be spammy keywords, shorter subject , etc. that is setup as one of the pattern to detect SPAM emails on IPAS engine (this is just an example, there could be various reasons too).

[EU-GDPR-CITIZEN]

Hey @Udupi Krishna.,

Actually I did open a TAC Case SR #692513247 and TALOS 2026101 ticket. I've shared the 'offending' email, had a WebEx and there's been much back-and-forth by email since.  But, nearly a fortnight on, I still don't have a clear text version of the content of the added X-IronPort-Anti-Spam-Result: and, as you say, the added X-IPAS-Result: header.  The recipient, and the recipent's IT Department have both given different, guessed, reasons.  Guesses aren't actionable; only a full understanding of the actual reason(s) the mail got tagged that way.

BTW, what's with this board?  The board's email your post (thank you) generated, gave a reply address of `ciscosupport.prod|a4bf1111|fd9fb2f3-34b5-447a-8dad-93f11b23cba5@replybyemail.usw2.prod.hosted.lithcloud.com`  but there's no MX; how can it accept replies by email?

[EU-GDPR-CITIZEN]

The tickets raised on TALOS: 2026101, 2026145, 2026157, 2027907, 2027911, 2027929 were all closed as resolved with no action taken, no translation of the X-IPAS-Result: header and no right of reply.  So, go-ahead.  I've posted both the X-IronPort-Anti-Spam-Result: and X-IPAS-Result: above, feel free to decode and tell me, free of guesses, why my email was tagged as [SUSPECTED SPAM].  TIA.