E-Mail sending to Offcie/Microsoft365 customers not possible - 451 4.7.500 Server busy

Koes 360 Reputation points
2023-10-11T10:38:11.0866667+00:00

Hi,

since this morning 5 am we are not able to send E-mails to office365/Microsoft365 Customers. Our Mails are stuck in our own queue and get the response: host customername.mail.protection.outlook.com 451 4.7.500 Server busy please try again later wit 193.228.149.133 S77719

Can someone check, why we are on an throtteling list with our E-MailServer and remove please?

Exchange Online
Exchange Online

A cloud-based service included in Microsoft 365, delivering scalable messaging and collaboration features with simplified management and automatic updates.

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  1. Deleted

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  2. IT Support Netwizard 0 Reputation points
    2023-10-11T15:04:39.54+00:00

    Same situation here.

    @Microsoft support @Outlook please whitelist 201.20.145.214, 201.20.145.231, 201.20.145.207, 201.20.145.210.

    Thank you

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  3. Carlo Preda 0 Reputation points
    2023-10-11T15:05:40.89+00:00

    11 ottobre 2023 alle ore 16:22 CEST

    Title: Some users may encounter delays receiving external email messages in Exchange Online User impact: Users may encounter delays receiving external email messages in Exchange Online. More info: Affected users may see a "451 4.7.500 Server busy" error message. Current status: We’re progressing with the testing and development stage of our fix, to ensure its efficacy prior to deployment. We expect to be able to provide an estimate time of completion by the time of the next scheduled update. Scope of impact: Impact is specific to some users who are served through the affected infrastructure. Start time: Monday, October 9, 2023 at 11:00 PM GMT+2 Root cause: A recent service update, applied to a section of infrastructure responsible for enforcing IP address anti-spam rules, contains a change which is inadvertently causing impact. Next update by: Wednesday, October 11, 2023 at 6:30 PM GMT+2

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  4. Lorenzo Ansaloni 0 Reputation points
    2023-10-11T15:06:38.3333333+00:00

    Same problem from Italy.

    Please add the following ip to whitelist:

    45.144.60.57

    45.144.60.16

    45.144.60.100

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