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how to fix this 550 5.1.8 Access denied, bad outbound sender AS(42004) for a not for profit

NAIDOC Management Committee 0 Reputation points
2024-04-12T02:06:11.22+00:00

our email seems to have been hacked and im trying to recover the email and i have changed the password.

Outlook Management
Outlook Management
Outlook: A family of Microsoft email and calendar products.Management: The act or process of organizing, handling, directing or controlling something.
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  1. SokiGuo-MSFT 28,541 Reputation points Microsoft Vendor
    2024-04-12T09:27:09.3566667+00:00

    Hi @NAIDOC Management Committee ,

    Welcome to our forum!

    What's your account? Exchange online? And does this issue occur with all users in your organization or some specific users?

    In addition, does this issue occur recently, if so, have you done any specific operations before that?

    Based on the error your provided, i found an article which mentioned that you received this NDR with error code 5.1.8 because your account has been blocked for sending too much spam. Typically, this problem occurs because your account has been compromised (hacked) by phishing or malware. It's suggested that you could refer to it and troubleshooting: Fix NDR error "550 5.1.8 Access denied" in Exchange Online.

    Hope to help you!

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