emails are bouncing back when sending to yahoo

I have owned a travel agency for 23 years and off and on this has been an ongoing problem. Most of the time I can tell my clients to look in their spam/junk folder and my emails are sitting there. Now they are no where to be found. I actually did a search on Microsoft and found people asking the same questions on how to fix this as far back as 2013....I stopped looking after that. I guess until they resolve this issue once again I will have to send emails from a Gmail account to get around this. But you would think as big of a company as Microsoft that they could resolve this quickly with the $$$$ they have to hire the best IT people.

I'm getting the same errors, and only when I send email to yahoo.com:

1/13/2024 3:53:26 PM - Server at MN2PR13MB3870.namprd13.prod.outlook.com returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to SocketError'
1/13/2024 3:52:24 PM - Server at mta5.am0.yahoodns.net (67.195.228.106) returned '421 4.4.2 Connection dropped due to SocketError'

I'm on Office Pro Plus 2016 using the desktop client, although it happens from the web client as well. My account is Microsoft 365 Business Basic.

I've tried sending to two different yahoo.com emails and I have sent at least 5 emails over 2 days.

The support article you listed presumes I'm using an old TLS version, but I'm using whatever Microsoft 365 supplies by default. Based on the fuller headers below, it's all TLS 1.2.

Original message headers:

Received: from CH0PR13MB5082.namprd13.prod.outlook.com (2603:10b6:610:ed::14)

 by MN2PR13MB3870.namprd13.prod.outlook.com (2603:10b6:208:1e9::20) with

 Microsoft SMTP Server (version=TLS1_2,

 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7181.21; Sat, 13 Jan

 2024 13:59:18 +0000

Received: from MW5PR13MB5878.namprd13.prod.outlook.com (2603:10b6:303:1c9::5)

 by CH0PR13MB5082.namprd13.prod.outlook.com (2603:10b6:610:ed::14) with

 Microsoft SMTP Server (version=TLS1_2,

 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7181.21; Sat, 13 Jan

 2024 02:55:19 +0000

ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none;

 b=DGeCf6TtbQRfJoqXMvaTrygs8ztPaSTX7pbbh7640MhFEsqRvZm5inAXsZ0aBCD0yqCPZ9vl+u+XzfSHdIm0B8xqfppBHPC0aqlDpDDZDAkF6ygttBjE2efHBCoyANaXLbsHC4VLOxZC8ve5v2AB8IEiUoIWxV7tAEyEsBAbn1jce4FTAC02ZgP0IAR16jFr36tlznqlt/F6tevE3uXI16GSGcu79YqM1oBmIeAqCQ5GAyliiz+PGrxvEDmqikuySULaZcoxt4gWlifNt/qn1GBxmQHEszveRzu2EKRkqkSzZ04ltElEb2hodRET+iEruR0YJMdWLJJGXreZhk1Tbw==

ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com;

 s=arcselector9901;

 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=pmF0dHM+eqWtinvkBnN3FlkywqX3KfqXGO+QxEwFxAU=;

 b=Ifx401K/pquhV5LSao1qwLLDqDtd/Coitmvtb4jbeoMBQspquKabvFMTBcSeHMIkR5wr1nci+ZPP6vJ1hj/PEryFmNzYC7kOEIxp+a/ryXK9BYA8ScJzzPfu+P6Cr0YeDCVGvAOV6cEnzFX+93VGG4fGUtq8sAdVIL6ZIqnU9Y6pSuH6GGcJwHRIvDYFqBnM3jzPUU62s3i6DUQCfDFpkBc07xBoLB01jf7XG1wmFLfUkxLJ1C5RisSjTTER/TBZTZ1WESPJl4yj6rGU79jaYRuQirDU22XVUCdtU01jratZ8v0gdXkoRLVd2NaCfbCvpmHHNo5DCvT559MihRX7Tw==

ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass

 smtp.mailfrom=larryseltzer.com; dmarc=pass action=none

 header.from=larryseltzer.com; dkim=pass header.d=larryseltzer.com; arc=none

DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;

 d=LarrySeltzer.onmicrosoft.com; s=selector2-LarrySeltzer-onmicrosoft-com;

 h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck;

 bh=pmF0dHM+eqWtinvkBnN3FlkywqX3KfqXGO+QxEwFxAU=;

 b=J6KTBOxh8gd/9BVQ1o4Wiz88qYhal/bam0GgmbrLfOn6jN0+ZSnl9OwnCa2Nbf5VcEFPgUfiJ6ksMpUPwYY//J0jIR9N1qEecNNUOPOcd3X7SVT8v0Mqqdf7KDZXyCzuY+vei2I+dRbG7yxZRHj72HAJzOGvi1lE9BikQQidIbw=

Received: from BLAPR13MB4578.namprd13.prod.outlook.com (2603:10b6:208:332::10)

 by MW5PR13MB5878.namprd13.prod.outlook.com (2603:10b6:303:1c9::5) with

 Microsoft SMTP Server (version=TLS1_2,

 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7181.18; Fri, 12 Jan

 2024 15:52:35 +0000

Received: from BLAPR13MB4578.namprd13.prod.outlook.com

 ([fe80::bfc2:9102:248f:3ec9]) by BLAPR13MB4578.namprd13.prod.outlook.com

 ([fe80::bfc2:9102:248f:3ec9%5]) with mapi id 15.20.7181.018; Fri, 12 Jan 2024

 15:52:35 +0000

From: Larry Seltzer <******@larryseltzer.com>

To: Miranda Aaron <******@yahoo.com>

Subject: RE: did you get this?

Thread-Topic: did you get this?

Thread-Index: AQHaRW8l29TU3qmeL0CC3dpEwkx787DWU56g

Date: Fri, 12 Jan 2024 15:52:35 +0000

Message-ID: <******@BLAPR13MB4578.namprd13.prod.outlook.com>

References: <******@mail.gmail.com>

 <******@yahoo.com>

In-Reply-To: <******@yahoo.com>

Accept-Language: en-US

thank you

Hello mpur,

Good day to you and thanks for your post in Microsoft community.

Regarding your post, may i are you sending email from Micrsooft365 business account? If so, based on the error message, we have checked and found official article, please check with SocketError when sending or receiving email messages - Exchange | Microsoft Learn and further assistance we recommend to contact Microsoft Technical team by either open ticket or phone support Get support - Microsoft 365 admin | Microsoft Learn (Note: only admin can open ticket, so if you don't have admin permission, kindly contact your admin and if you purchase Microsoft services from partner, please contact your partner).

If your sending email account is belonging from outlook.com/live.com/hotmail.com side, please reply back to us, so we can involve dedicated team for further assistance.

Thank you for your time and cooperation.

Sincerely,

Ankita Vaidya

Hello mpur,

Good day!

Thank you for posting to Microsoft Community. We are glad to assist.

We are looking into your situation and we need sometime to do further research on this. Will update the thread shortly.

Appreciate your patience and understanding and thank you for your time and cooperation.

Sincerely,

Microsoft Community