Request to remove outbound mail restriction (550 5.7.708 AS(7910)) for new tenant

Ofer Lavan 0 Reputation points
2025-10-01T12:08:19.63+00:00

Hello Microsoft Support,

I’m requesting assistance to remove a low-reputation outbound mail restriction on our new Microsoft 365 tenant.

  • Tenant ID: <Removed PII>

Primary scenario: We’re developing an application that uses Microsoft Graph (app-only) to create Teams meetings and send calendar invitations to external attendees (via POST /users/{organizer}/events and occasional .../forward or ?sendUpdates=all).

Organizer mailbox/sender: <Removed PII>****.com (Microsoft 365 Business Premium)

External recipient example:<Removed PII>.com

What we observe

Events are created successfully and the mailbox shows Sent Items for both the original invitation and forwards (so Exchange is generating mail).

However, message trace indicates outbound delivery is blocked:

Get-MessageTraceV2 shows Status = Failed

  **MessageTraceId:** `<Removed PII>`

  
     **Detail (Get-MessageTraceDetailV2):** `550 5.7.708 Service unavailable. Access denied, traffic not accepted from this IP. For more information please go to http://go.microsoft.com/fwlink/?LinkId=<Removed PII> AS(7910)`

From Microsoft’s documentation, this appears to be the new/low-reputation tenant outbound block. We need to send meeting invitations to external recipients as part of our product workflow.

Request Could you please review and remove the 5.7.708 outbound restriction (AS(7910)) for tenant <Removed PII>, or apply the necessary exception so Exchange Online can deliver our outbound mail?

Additional notes

We can provide more recent MessageTraceIds on request.

We plan to send from our custom domain and will configure SPF/DKIM/DMARC accordingly, but currently the issue reproduces even from the onmicrosoft.com address.

If there are any specific validation steps you’d like us to complete, please let us know.

Thank you very much for your help!

Best regards, Ofer Lavan GROH SystemsHello Microsoft Support,

I’m requesting assistance to remove a low-reputation outbound mail restriction on our new Microsoft 365 tenant.

Tenant ID: <Removed PII>

Primary scenario: We’re developing an application that uses Microsoft Graph (app-only) to create Teams meetings and send calendar invitations to external attendees (via POST /users/{organizer}/events and occasional .../forward or ?sendUpdates=all).

Organizer mailbox/sender: <Removed PII>****.com (Microsoft 365 Business Premium)

External recipient example: <Removed PII>****.com

What we observe

Events are created successfully and the mailbox shows Sent Items for both the original invitation and forwards (so Exchange is generating mail).

However, message trace indicates outbound delivery is blocked:

Get-MessageTraceV2 shows Status = Failed

 **MessageTraceId:** `

From Microsoft’s documentation, this appears to be the new/low-reputation tenant outbound block. We need to send meeting invitations to external recipients as part of our product workflow.

Request Could you please review and remove the 5.7.708 outbound restriction (AS(7910)) for tenant <Removed PII>, or apply the necessary exception so Exchange Online can deliver our outbound mail?

Additional notes

We can provide more recent MessageTraceIds on request.

We plan to send from our custom domain and will configure SPF/DKIM/DMARC accordingly, but currently the issue reproduces even from the onmicrosoft.com address.

If there are any specific validation steps you’d like us to complete, please let us know.

Thank you very much for your help!

Best regards,
<Removed PII>

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. Hin-V 16,830 Reputation points Microsoft External Staff Moderator
    2025-10-01T12:39:15.24+00:00

    Hi @Ofer Lavan

    Thank you for posting your question in Microsoft Q&A. 

    Please understand that our forum is a public platform, and we will modify your question to cover your organization domain name in the description. Please notice to hide these personal or organization information next time you post error or some information to protect personal data. 

    We understand that you are requiring to remove outbound mail restriction to your new tenant. We are glad to assist you this part. 

    The "550 5.7.708 Service unavailable. Access denied, traffic not accepted from this IP" respond is indeed a security measure Microsoft applies to new tenants to prevent potential spam and abuse while a sending reputation is established. 

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    You can refer via: NDR error codes 550 5.7.703, 550 5.7.705, 550 5.7.708, and 550 5.7.750 - Microsoft Support

    To resolve this, I recommend you raise a support ticket via Admin Center. 

    The support team will help you with this issue. 

    User's image

    If you have any additional concerns, feel free to comment below. I would be more than happy to assist.

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".      

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread. 

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