outgoing email blocked due to 5.7.705 error message

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outgoing email blocked due to 5.7.705 error message

Richard Smith 20

outgoing email blocked due to 5.7.705 error message. Need to unblock. Have changed password, deleted connectors. Can call Microsoft

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Answer 1

Error 5.7.705 means: Access denied, tenant has exceeded threshold. Exchange Online has detected that most of the outbound traffic from the tenant looks like spam or bulk mail, so it has blocked sending.

Changing passwords and deleting connectors are good first steps, but the block will not clear automatically. An email admin must both fix the underlying cause and then contact Microsoft Support to remove the block.

Recommended steps for the email admin:

Verify and remediate compromise or abuse
- Check for compromised accounts or on-premises servers that might be relaying spam to Exchange Online. Use:
  - Responding to a compromised email account
- Ensure multifactor authentication (MFA) is enabled for all admin and high‑risk accounts:
  - Set up multifactor authentication for Microsoft 365
- Review and harden tenant-wide security configuration:
  - Configure your Microsoft 365 tenant for increased security
- Review Microsoft Secure Score and apply recommended improvements:
  - Microsoft Secure Score
Confirm no misconfiguration is causing bulk or suspicious traffic
- Double‑check any remaining connectors for correctness and necessity.
- Ensure there are no open relays or automated systems sending large volumes of mail through the tenant.
Contact Microsoft Support to remove the block
- After confirming that the compromise or misconfiguration is resolved and outbound traffic is clean, the tenant admin must open a support case with Microsoft.
- Clearly state that outbound mail is blocked with NDR 5.7.705 Access denied, tenant has exceeded threshold, and that remediation steps have been completed.
- Microsoft Support will review the tenant’s status and, if satisfied that the risk is mitigated, remove the sending block.

Until Support removes the block, outbound mail from the tenant will continue to fail with 5.7.705 even if passwords and connectors have been changed.

References:

Richard Smith 20 Reputation points

2026-03-18T15:52:08.6766667+00:00

Item 3 stated "Contact Microsoft Support to remove the block", but how do I do this?

Answer 2

Matthew-P 11,900 Microsoft External Staff Moderator

Hi Richard Smith,

To answer your question on how to contact Microsoft Support to remove the block, please follow these steps in the Microsoft 365 Admin Center:

1. Log in to the Microsoft 365 Admin Center using your Global Admin credentials.

2. Look for the "Help & support" widget (usually a headset icon) located at the bottom right corner of the screen.

User's image

3. In the search box, type: "Exchange Online blocked error 5.7.705" and press Enter.

4. Scroll to the bottom of the suggested articles and click the blue "Contact Support" button.

5. Fill in the form: "We are receiving NDR 5.7.705. We have remediated the compromise. Please unblock our tenant."

6. Click "Contact me".

Once the ticket is created, it will be routed to the Microsoft Support team. Since you have already fixed the security issues, they typically proceed to unblock the tenant after verification.

For full detailed instructions, you can refer to the official documentation here: Get support for Microsoft 365 for business

I hope this information is helpful to you. If you have any further concerns or questions, or if I misunderstood anything or if any part of the instructions is unclear, please feel free to reach out anytime.

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.

Matthew-P 11,900 Reputation points Microsoft External Staff Moderator

2026-03-20T06:30:50.2166667+00:00

Hi Richard Smith,

I hope you're doing well. Just reaching out to see if you've had a chance to review the responses shared earlier.

If you have any updates or further questions, please feel free to share.
Richard Smith 20 Reputation points

2026-03-20T08:09:01.09+00:00

Hi - all makes sense, but I’m not global admin. This was by my reseller and retained by them. The partner roles were reset apparently by Microsoft a while back and have now lost their partner role. Real problem accessing Microsoft by phone!
Matthew-P 11,900 Reputation points Microsoft External Staff Moderator

2026-03-23T04:42:20.32+00:00
Hi Richard Smith,

Since you mentioned you are having trouble reaching a real person at Microsoft Support due to the AI Bot, here is a specific tip you can try to bypass it:

1. Tip to bypass the AI Bot via Phone:

The call must include the keyword "Admin Center", and your role must be specified as "Global Administrator".

In the voice description of your request, the term "Admin Center" must also be mentioned clearly.

This sequence usually triggers the system to forward the call to a human agent.

Reference: You can check this discussion here: [article] What to do if Microsoft Authenticator is not available and you can't sign in to your organization account

(Note: The linked page is in Japanese, so please use a translator when reviewing it).

2. Regarding your Reseller and the "Lost Partner Role": The most critical step right now is to clarify the access with your Partner. When they say they "lost partner roles," it likely refers to Microsoft's recent security transition (GDAP), where old partner links were removed.

However, even if the Partner link is broken, the tenant itself is not gone. There is usually a specific local Global Admin account on your tenant that ends in @yourcompany.onmicrosoft.com.

Please contact your Reseller immediately and ask if they have the credentials (username/password) for this specific .onmicrosoft.com admin account.

If they have it, you (or they) can log in directly to admin.microsoft.com using that account and open the ticket online as I instructed previously.

Please understand that this is a peer-to-peer community forum. We are users helping users; we do not have access to your account or Microsoft's backend tools to lift the block on your behalf. We can only guide you based on our experience and how we have helped many other users in similar situations.

I hope this information helps you regain control. If you have any further questions or if anything is unclear, please feel free to reach out anytime.
Matthew-P 11,900 Reputation points Microsoft External Staff Moderator

2026-03-24T06:35:57.19+00:00

Hi Richard Smith,

Just wondering if there’s been any progress on this thread.

Any updates you can provide would be greatly appreciated.
Richard Smith 20 Reputation points

2026-03-24T07:51:49.96+00:00

Thanks for the advice - really useful. I rand Microsoft twice on Friday and actually managed to speak to someone. This was followed by two more calls from Microsoft on Monday, so I feel like we’re getting there. Now security checked so waiting for the Global Admin account to be reset. They seem unwilling to discuss multiple issues (like needing to get my mailbox unblocked for outgoing email) - but I’ll reserve judgement until they’ve actioned this current issue. I did get an email stating this was urgent category C and it would be resolved in 8 hours - but 20 hours later I’ve still not heard from them again. Hoping it gets resolved today,
Richard Smith 20 Reputation points

2026-03-24T17:59:55.22+00:00

Update: Global Admin now restored, but still can’t sen emails, despite asking for the account to be unblocked. Checked in Defender and there are no blocked accounts.
Matthew-P 11,900 Reputation points Microsoft External Staff Moderator

2026-03-25T00:57:46.5666667+00:00
Hi Richard Smith,

This is great news! Regaining Global Admin access was the hardest part, and I'm glad the phone strategy worked. We are almost at the finish line.

To clarify your confusion about why you still can't send emails and why Defender shows "no blocked accounts":

Error 5.7.705 is a Tenant-Level Block (blocking your entire organization's IP/Pool), not a specific User-Level Block. The "Restricted entities" page in Defender only shows individual users restricted for sending spam. Since Microsoft blocked your whole tenant/IP, individual users won't appear there.

Microsoft Support strictly follows a "One issue per ticket" policy. The previous agent's job was solely to restore your access. Now that the ticket is closed/resolved, a new process for the email block must be started.

Now that you have Global Admin access, you can bypass the phone support entirely. You can now open a direct technical ticket from the portal, which goes straight to the backend engineers.

Please go ahead and create the support ticket following the detailed instructions I provided in my initial answer. Since you are now authenticated as an Admin, this ticket will be routed to the correct engineering team much faster than calling the general hotline.

You are at the final step now. Fingers crossed for a quick resolution!

Hope this helps. If you have any updates or further questions, please feel free to share anytime. I'm always here to help.
Matthew-P 11,900 Reputation points Microsoft External Staff Moderator

2026-03-26T05:25:47.2333333+00:00

Hi Richard Smith,

Just wondering if there’s been any progress on this thread.

If you still have any updates or questions, please don’t hesitate to let me know.

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outgoing email blocked due to 5.7.705 error message

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