My outgoing emails are blocked as spam

Question

My outgoing emails are blocked as spam

Segretario Loggia Galileo 0

I'm a club secretary and members send me .pdf file to share. I can receive them but when I try to send to members (names in a list) or even just to myself they get blocked as spam.

see below. This has started last 2 weeks, firstly only to bigpond.com adressee now to everyone.

Diagnostic information for administrators:

Generating server: SE1P216MB1304.KORP216.PROD.OUTLOOK.COM

******@bigpond.net.au exhprdmxe03 Remote server returned '554 5.7.1 <exhprdmxe03 #5.7.1 smtp;550-5.7.1 ******@outlook.it Sender domain rejected. IB302 550 5.7.1 i{3e9560d0-8c27-4e89-9cbc-809777fbe130}>'

Original message headers:

ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none;
 b=KA1anEAlQmpW1gAqImyreXpDmsvqtB4k4B1XXQyRCAaN6j7NRHBvCO7dokCDffKZ7ZFwxvPVEzZQyrJjaOjUNgquZpnHBEB9YTcWjxfooy0kwwRhC4DRaDFhYyGZBcCGlb8Oh3qnbIcPBUdlGA26P447iX0iJrrTvb91HWMwtzbSyxc8gCdnngBB3bGStr2S0Rkj3wNc08DZXiqEoJPtf4hPDUjfayhYXyvw6GADx6MyQyQSmNBCM2YLiEIId7kkvMsqW9lDEIGEjYZYUrvw+2IaAS3Owq36rDIiqwpM9Gi2Wzs+fqvkiQU/FNCxdhPgxL97/EKEZHrwQi8bY5nmTA==
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com;
 s=arcselector10001;
 h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1;
 bh=BzgMj9Co1zFyIopSwH8Zi8g51Dez7tD3BqM6p5zq2qA=;
 b=af/BhcTIylUAtP75tsbwP3or1Yd0d6iE2nF0Y2RKbaKwclDwM6rE/6YUY8sZchd9Ng81bRpoldnNaZ8h3VqAcckmCI0wNKcWcfbXE438Z3iBQrx7S128x5cu0f8wZiNWFHFPVvxIw2z5uW5D0Eps6Fwc8HAQnc/56IdGdOm4Y+PHwi1NLvHT9VTH2A6WIc5zpvtIvT1z684286Qu3/iNWwRreUBhXvPcRQS2qBw5mnYpi6X5/c2dc8jCEBYomxMSy8XC5t4CO8lO3OMXmrZbARfAwuzyClvnwbPciKWCdP0PaZa1CE5PkNT2AGRUoMTpAn+s+0cIgEgVQqpZCgx33w==
ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=none; dmarc=none;
 dkim=none; arc=none
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=OUTLOOK.IT;
 s=selector1;
 h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck;
 bh=BzgMj9Co1zFyIopSwH8Zi8g51Dez7tD3BqM6p5zq2qA=;
 b=ughwW1RnP9W+7xQ/o1MhKT6DlrDHgz8+Oznyj8CqJZLBoOvC41/Z6q2+dZIkmvIiGsh3mjEFYlQva/fh63A3fqCM1aVwMatQtK4ubcRZr05rO+FpEpvcekx4jYDiXQ5aiCNqlwOp4yrG0d1nXUl6KHGldvHCu9RjwzdLnInW/Wrcm/Sr4nvru+WoGlMbDPARhJym8pdUCwTISAmKZFPxApaUUKAjAuaTynox/PEz3/2BEt1LEHZKEYUqdogoOYw+RXzJ5ZW1+pmbMnTR1vbaw0G+6GFBTVF4uqJahHEGXyWKnHcHldXT5Zo8gFhv9m/VHsCW8vIg+az3u4LoB5iw3Q==
Received: from PUUP216MB3328.KORP216.PROD.OUTLOOK.COM (2603:1096:301:169::23)
 by SE1P216MB1304.KORP216.PROD.OUTLOOK.COM (2603:1096:101:14::6) with
 Microsoft SMTP Server (version=TLS1_2,
 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.315.17; Mon, 17 Aug
 2026 01:13:40 +0000
Received: from PUUP216MB3328.KORP216.PROD.OUTLOOK.COM
 ([fe80::959b:89ea:55f1:3707]) by PUUP216MB3328.KORP216.PROD.OUTLOOK.COM
 ([fe80::959b:89ea:55f1:3707%5]) with mapi id 15.21.0315.016; Mon, 17 Aug 2026
 01:13:40 +0000
From: Segretario Loggia Galileo <******@outlook.it>

Hornblower409 14,690 Reputation points

2026-08-18T06:22:29.85+00:00

If the AI Answer did not solve your problem, type "Not Solved" in the "Add Comment" box below and then click the [Add Comment] button. I will try to offer some suggestions on what you can do next.

If you recently tried to add an Answer to this thread, it was Deleted by the forum Spam filters.

2 answers

Your answer

Hornblower409 14,690 Reputation points

2026-08-18T06:22:29.85+00:00

If the AI Answer did not solve your problem, type "Not Solved" in the "Add Comment" box below and then click the [Add Comment] button. I will try to offer some suggestions on what you can do next.

If you recently tried to add an Answer to this thread, it was Deleted by the forum Spam filters.

Answer 1

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Answer 2

The rejection shown is from the recipient side: 554 5.7.1 ... Sender domain rejected. That means the receiving mail system is refusing the message, and the recipient’s provider decides whether to accept it.

Based on the symptoms and the headers shown, the most relevant checks are:

Send a plain test message with no PDF, no links, no images, and no signature.
- If that succeeds, the message content or attachment is contributing to the spam decision.
Avoid sending the PDF as a direct attachment.
- Outlook blocks some attachment types for safety, and for files that trigger filtering, the recommended alternative is to save the file to OneDrive and send a link instead.
- Another supported alternative is to compress the file into a .zip before sending.
If the message is going to a group or mailing list, review the recipient addresses.
- Remove any old or invalid addresses from the group.
If the rejection mentions blocking, blacklist terms, or the recipient server intentionally blocking the message, contact the support team for the recipient’s email provider and request that the account or domain be unblocked.
If Outlook.com delivery problems continue and they are specific to Outlook.com addresses such as @outlook.com, @hotmail.com, @live.com, or @msn.com, use the Outlook.com sender support troubleshooting form.
If the account is being treated as suspicious for sending, check whether the account may be compromised and review recent sending activity.

Because this started recently and now affects multiple recipients, the most practical end-to-end test is:

first send a short plain-text email to the same recipient,
then send the same message with no attachment but with the recipient list,
then replace the PDF attachment with a OneDrive link.

If plain text works but the PDF version fails, keep using a OneDrive link or .zip for the file. If even plain text fails, the recipient provider is likely blocking the sender/domain and the unblock path is with that provider or Outlook.com sender support for Outlook.com destinations.