Outlook Error Codes

How to Fix Outlook Error 550 5.7.708 (Access Denied from This IP)

Ayan Masood Oct 13, 2026 869 views

Question details

The user is unable to send outbound emails due to an Access Denied from this IP restriction (Error code 550 5.7.708).

How to Fix Outlook Error 550 5.7.708 (Access Denied from This IP)

Product: Microsoft Outlook
Device & OS: not provided
Scenario: Attempting to send an outbound email via Microsoft 365 or the Outlook desktop application.
Observed behavior: Outlook blocks the outgoing email and displays error 550 5.7.708, indicating the sender's IP address or account has been blocked due to suspected spam or poor IP reputation.

Before you start

Make sure to copy the entire bounce-back error message, as you will likely need to provide these details to your organization's IT administrator to lift the restriction.

Solution 1Recommended

Contact Your IT Administrator to Unblock Your IP

Since Error 550 5.7.708 is typically a tenant-level restriction enforced by Microsoft 365, your organization's IT administrator must resolve it in the Microsoft Defender portal.

Microsoft 365 automatically blocks IP addresses or email accounts that show patterns of sending spam or suspicious bulk emails. End users usually do not have the necessary permissions to unblock themselves.

Copy the Error Message

Open the bounced email notification you received and copy the complete text, paying special attention to the server codes and the 550 5.7.708 error reference.

Contact IT Support

Forward the bounce message or paste the text into a support ticket directed to your organization's IT administrator.

Request Account Unblocking

Ask your administrator to log into the Microsoft Defender portal, navigate to the 'Restricted entities' page, and delist your affected email account or IP address.

Processing Time: Once the administrator removes the restriction from the Microsoft Defender portal, it can take anywhere from a few minutes to a few hours for the changes to propagate across Microsoft's servers.

Solution 2

Troubleshoot the Outlook Desktop Client

If you are only experiencing this issue in the Outlook desktop application but can send emails normally via Outlook on the web, a local application issue might be the cause.

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Frequently Asked Questions

What does Outlook Error 550 5.7.708 mean?

This error means that Microsoft 365 or the recipient's email provider has blocked your IP address or sending account. This usually happens when the system detects suspicious activity, a compromised account, or outbound spam originating from your address.

Can I fix Error 550 5.7.708 by myself without an administrator?

Generally, no. Since the block is enacted at the organization or tenant level by Microsoft's security protocols, an IT administrator with the proper permissions must log into the Microsoft Defender portal to unblock the restricted entity.

Why would my IP address get a poor reputation?

An IP address can develop a poor reputation if a device on your network is infected with malware sending automated spam, if you are sending bulk emails that get marked as spam by recipients, or if you are using a new IP address that hasn't established a trustworthy history yet.

Does Error 550 5.7.708 stop me from receiving emails?

No, this error specifically blocks outbound traffic (sending emails). You should still be able to receive incoming emails without any issues while the sending block is active.

Microsoft Office Error Codes