Email to tmomal.net from hotmail.com not getting thru

I’m seeing this same error.

This is still an issue.  

Delivery has failed to these recipients or groups:
number_suppressed@tmomail.net (number_suppressed@tmomail.net)
Your message couldn't be delivered. Despite repeated attempts to contact the recipient's email system it didn't respond.
Contact the recipient by some other means (by phone, for example) and ask them to tell their email admin that it appears that their email system isn't accepting connection requests from your email system. Give them the error details shown below. It's likely that the recipient's email admin is the only one who can fix this problem.
For more information and tips to fix this issue see this article: https://go.microsoft.com/fwlink/?LinkId=389361.

Diagnostic information for administrators:
Generating server: BL1PR12MB5253.namprd12.prod.outlook.com
Receiving server: BL1PR12MB5253.namprd12.prod.outlook.com 
Total retry attempts: 14
number_suppressed@tmomail.net
4/18/2023 12:57:58 AM - Server at BL1PR12MB5253.namprd12.prod.outlook.com returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to SocketError'
4/18/2023 12:41:23 AM - Server at tmo-east.mx.a.cloudfilter.net (34.232.155.8) returned '421 4.4.2 Connection dropped due to SocketError'
Original message headers:
Received: from BL1PR12MB5045.namprd12.prod.outlook.com (2603:10b6:208:310::15)
 by BL1PR12MB5253.namprd12.prod.outlook.com (2603:10b6:208:30b::22) with
 Microsoft SMTP Server (version=TLS1_2,
 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6298.45; Mon, 17 Apr
 2023 13:07:55 +0000
ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none;
 b=Wd3EE94+RqF3D8eQVSL05GhlrBVA5G/w931xp8tXmWT1hQHEUkqqZLlTPieZ29R4VHuUien5tMsI01ll1ZLX94EcCSMvi/KWy1wx5wHqZn8oRB79haDErkCM6+I218mUm1elNlvcqgWA69Ux2W9ceKWSVWPHPPC1BBbO8UXbggDzfEDE/DTV4Z+fEJ0ZnoOsn8kNx0ivUlwxy5cLh2LuSXnLXHSdSdMKe537C5DVvlPrbarBQTBCUjhWUat7QV36cYP/yGKjJmzrDWo8P9SWQ4zZKc1inu5uvGsV7dpkki17xRtWuGZ85TlwM3QgQzXrE5SQMcQQkj6zBw9zrQXUrQ==
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=QSOzGjWQBx3gwlv7MPyst6FKVRAWLMw2C8k5/g3/uDA=;
 b=i2OJO7DBxhiOsrRSkbDgLc4nus1GJIxU2pF/2cl2C6JZBXcZ5WU6DczCeByq6YmhfITemWBu1riPZwjcB4m5A7i85iCFhR0n9HFKtsKG6DD7YV9Sfgxk5A/HZ5aA+a/6YUeK26RYYOO8m0SkhLutD1Ix822fwTebg0NN3N8XRdubhAddLa2ohe79naxyLjdpQi0OkmN0d2qll/RCOm1o15DxQnq9Pa7uQeG5UaEtAry1QOOidU3Vc5b/TSZYS7Yr6bNkiotrEcNcJZSCf42TD/mVL3MPvVSTKt3Q5nYXTAcsY5gdghqtQ1DrT3gosnfo62rl8eszopE+/m232gE7sQ==
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=hotmail.com;
 s=selector1;
 h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck;
 bh=QSOzGjWQBx3gwlv7MPyst6FKVRAWLMw2C8k5/g3/uDA=;
 b=Mo6vUPlsjvJQq+lbbBeVBWdh49FWXU4WbrxKKdaLVe171UR5DYcTiG/jFg747UDUrRDSO1c66Kb3gNRrAphwf35y6aWjTA8kBBgLy3Wj+h//Vl5stzs/zzbJGym9HNwGwiT48dMm1x2iSiH62nyD2e/ZeXEUctH+CXX0P75+4UNW8ruk3pLQSgBwyJCTCzumrb3C56+WYACw3xoRVpVreS5jj7bDebx+JOkPAz0IScODbZoSYuZwTjxBTgZ8tIDbZ88u/k/imkCAxW5NAO6Nd4bKPX2jZiK+8gniNm80snTAsxWL1CtWQ2XN0zydPbLAgjNTySqka4C+SacXX5JekA==
Received: from PH7PR12MB5830.namprd12.prod.outlook.com (2603:10b6:510:1d5::15)
 by BL1PR12MB5045.namprd12.prod.outlook.com (2603:10b6:208:310::15) with
 Microsoft SMTP Server (version=TLS1_2,
 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6298.45; Mon, 17 Apr
 2023 00:57:57 +0000
Received: from PH7PR12MB5830.namprd12.prod.outlook.com
 ([fe80::a2d3:365b:fa3:68c8]) by PH7PR12MB5830.namprd12.prod.outlook.com
 ([fe80::a2d3:365b:fa3:68c8%6]) with mapi id 15.20.6298.045; Mon, 17 Apr 2023
 00:57:57 +0000
From: David name_suppressed <email_suppressed@hotmail.com>
To: "number_suppressed@tmomail.net" <number_suppressed@tmomail.net>
Subject: test
Thread-Topic: test
Thread-Index: Adlwx6P964P/zmikR/CexRN7RxGsTg==
Date: Mon, 17 Apr 2023 00:57:57 +0000
Message-ID: <PH7PR12MB583087CA15FCF7A1F174900FC89C9@PH7PR12MB5830.namprd12.prod.outlook.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-tmn: [orvNYflmtXwqOgYSNDJkocSsmEFXagh3]
x-ms-publictraffictype: Email
x-ms-traffictypediagnostic:
    PH7PR12MB5830:EE_|BL1PR12MB5045:EE_|BL1PR12MB5253:EE_
x-ms-office365-filtering-correlation-id: 2cf23b8b-f6e9-4837-6522-08db3edec8c2
x-microsoft-antispam: BCL:0;
x-microsoft-antispam-message-info: BImkF/ystE3eeNG3nKw7/PBkNMcxwjOevuEI3Q2nQNGMska9h7Y+3Vl16FNfknv8h57Vf5ZLc1sDc/v5iyY3ryQMqCQp8afP20SaUU43Ej1efi5SKt8TEgPwEujF5UMc59lPWhxc3ihPWdlVGu+M7WjWM3GVr1IaAVLDqUhIy2QrPiivKHlzBvTvACod5DQay7msKxDK3NI/F2nKC17yqKh+QUiaJBEHNSlwVF5hcUjDQKZ9CzwO53rxL9GgSDWK8NIPW07SwW8qkGMDvvfqSW4yJL7OADfUPAEfOgCMYZU=
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?hu4K8fP8MK2c3GT5Sw3LM+3BZ01y5s2v0bHBhEUIPSH9YpFfGtrQ28mS4+Im?=
 =?us-ascii?Q?fjPkPahwJkBIjoRTREDiojo4WG9RisQbxFGTB+RAiwzSITN4tEo3GiCG9bTx?=
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 =?us-ascii?Q?eRhwsgC7QSuAadtPy5kHarltpmLet3+L8dL8AfuBoXc/Tk9qROCwNxf/CnAh?=
 =?us-ascii?Q?k7g0ur9EuUaYeEAfJZOwLn3GMtaMGJ3mK5oSxVVFQHNBv9JtzvExAynGjIj5?=
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Content-Type: multipart/alternative;
    boundary="_000_PH7PR12MB583087CA15FCF7A1F174900FC89C9PH7PR12MB5830namp_"
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5830.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000
X-MS-Exchange-CrossTenant-Network-Message-Id: 2cf23b8b-f6e9-4837-6522-08db3edec8c2
X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Apr 2023 00:57:57.4883
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa
X-MS-Exchange-CrossTenant-rms-persistedconsumerorg: 00000000-0000-0000-0000-000000000000
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5045
Return-Path: email_suppressed@hotmail.com
X-OriginatorOrg: sct-15-20-4755-11-msonline-outlook-71ea3.templateTenant
 

I’m experiencing the same issue with my hotmail account as well.  Looks like a tmobile issue:

Server at tmo-west.mx.a.cloudfilter.net (35.85.199.61) returned '421 4.4.2 Connection dropped due to SocketError'

Generating server: MWHPR04MB0639.namprd04.prod.outlook.com
Receiving server: MWHPR04MB0639.namprd04.prod.outlook.com
Total retry attempts: 14

+1XXXXXXXXXX@tmomail.net
5/16/2022 10:10:37 PM - Server at MWHPR04MB0639.namprd04.prod.outlook.com returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to SocketError'
5/16/2022 9:46:46 PM - Server at tmo-west.mx.a.cloudfilter.net (35.85.199.61) returned '421 4.4.2 Connection dropped due to SocketError'