Communication failure for senders to my hotmail address

Question

A communication failure occurred during the delivery of this message. Please try to resend the message later. If the problem continues, contact your email admin.

DU6PEPF0000A7DD.mail.protection.outlook.com gave this error:

Requested action not taken: mailbox unavailable (S2017062302). [DU6PEPF0000A7DD.eurprd02.prod.outlook.com 2025-01-20T19:44:56.880Z 08DD3758B1250C3E]

Diagnostic information for administrators:

Generating server: PAXP251MB0027.EURP251.PROD.OUTLOOK.COM

@hotmail.com

DU6PEPF0000A7DD.mail.protection.outlook.com

Remote server returned '550 5.5.0 Requested action not taken: mailbox unavailable (S2017062302). [DU6PEPF0000A7DD.eurprd02.prod.outlook.com 2025-01-

20T19:44:56.880Z 08DD3758B1250C3E]'

Answer 1

Hi @Maarten Eestermans

Looks like the issue is more related to your Hotmail account, please kindly understand that the Outlook tag here we mainly focus on general issues about Outlook desktop client. It's suggested that you could post your case in dedicated forum for Hotmail for more professional advice.

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According to the error code, the recipient's domain is @hotmail.com or @outlook.com and it wasn't found by SMTP address lookup.<SMTP Address>.

For more information, see Fix email delivery issues for error code 550 5.1.10 in Exchange Online.

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