Sendgrid email are marked as SPAM by Outlook

Question

Hi there.

I'm trying to send Firebase Authentication to company emails (@something.com) that are using Outlook 365.

Since all email were marked as SPAM, I moved Firebase the a Sendgrid SMTP in order to get the email in the normal boxes.

Also with Sendgrid, emails are arriving to SPAM folder and I don't know why.

For example, Gmail is not marking them as SPAM.

Here you got the message header.

Received: from HE1PR0101MB2426.eurprd01.prod.exchangelabs.com (2603:10a6:3:7e::12) by VI1PR01MB6446.eurprd01.prod.exchangelabs.com with HTTPS; Thu, 7 Oct 2021 12:53:23 +0000 Received: from AS9PR06CA0302.eurprd06.prod.outlook.com (2603:10a6:20b:45b::17) by HE1PR0101MB2426.eurprd01.prod.exchangelabs.com (2603:10a6:3:7e::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4566.13; Thu, 7 Oct 2021 12:53:22 +0000 Received: from VE1EUR01FT062.eop-EUR01.prod.protection.outlook.com (2603:10a6:20b:45b:cafe::b) by AS9PR06CA0302.outlook.office365.com (2603:10a6:20b:45b::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4566.16 via Frontend Transport; Thu, 7 Oct 2021 12:53:22 +0000 Authentication-Results: spf=pass (sender IP is 149.72.40.63) smtp.mailfrom=em5854.MYDOMAIN.COM; live.it; dkim=pass (signature was verified) header.d=MYDOMAIN.COM;live.it; dmarc=bestguesspass action=none header.from=MYDOMAIN.COM;compauth=pass reason=109 Received-SPF: Pass (protection.outlook.com: domain of em5854.MYDOMAIN.COM designates 149.72.40.63 as permitted sender) receiver=protection.outlook.com; client-ip=149.72.40.63; helo=wrqvnvpf.outbound-mail.sendgrid.net; Received: from wrqvnvpf.outbound-mail.sendgrid.net (149.72.40.63) by VE1EUR01FT062.mail.protection.outlook.com (10.152.3.68) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4587.18 via Frontend Transport; Thu, 7 Oct 2021 12:53:21 +0000

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X-SID-Result: PASS

X-MS-Exchange-Organization-PCL: 2

X-MS-Exchange-Organization-SCL: 0

X-Microsoft-Antispam: BCL:0;

Please note that I cannot edit the settings of the company emails, and I cannot ask someone to do that

Answer 1

Hi giovanni256,

Thank you for choosing Microsoft community.

Microsoft 365 for business mailboxes (work account) rely on Exchange Online Protection (EOP) to filter messages. Based on my knowledge, since the spam confidence level (SCL) value and the bulk complaint level (BCL) value are both 0, indicating the EOP judged the message not likely to be spam. For your reference: Anti-spam message headers - Office 365 | Microsoft Docs

 

So I'd like to suggest that if you can confirm the security of Firebase Authentication messages, you may ask the recipient to mark the message as Not Junk and put the sender into Safe Senders list. See Overview of the Junk Email Filter (microsoft.com) .

You may also contact the Microsoft 365 (Exchange) admin to confirm if there's any transport rule set which is related with this issue.

Hope it helps! If any update, welcome to share with us.

Thanks & Stay safe,

Qian

Answer 2

Hi giovanni256,

Hope everything goes well with you.

Regarding your concern, may I know if there is any update? Thank you!

Sincerely,

Qian