Remove blocked users from the Restricted entities page
Tip
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In Microsoft 365 organizations with mailboxes in Exchange Online or standalone Exchange Online Protection (EOP) organizations without Exchange Online mailboxes, several things happen if a user exceeds the outbound sending limits of the service or the limits in outbound spam policies:
The user is restricted from sending email, but they can still receive email.
The user is added to the Restricted entities page in the Microsoft Defender portal.
A restricted entity is a user account or a connector that's blocked from sending email due to indications of compromise, which typically includes exceeding message receiving and sending limits.
If the user tries to send email, the message is returned in a non-delivery report (also known as an NDR or bounce message) with the error code 5.1.8 and the following text:
"Your message couldn't be delivered because you weren't recognized as a valid sender. The most common reason for this is that your email address is suspected of sending spam and it's no longer allowed to send email. Contact your email admin for assistance. Remote Server returned '550 5.1.8 Access denied, bad outbound sender."
For more information about compromised user accounts and how to regain control of them, see Responding to a compromised email account.
The procedures in this article explain how admins can remove user accounts from the Restricted entities page in the Microsoft Defender portal or in Exchange Online PowerShell.
For more information about compromised connectors and how to remove them from the Restricted entities page, see Remove blocked connectors from the Restricted entities page.
What do you need to know before you begin?
You open the Microsoft Defender portal at https://security.microsoft.com. To go directly to the Restricted users page, use https://security.microsoft.com/restrictedusers.
To connect to Exchange Online PowerShell, see Connect to Exchange Online PowerShell.
You need to be assigned permissions before you can do the procedures in this article. You have the following options:
Microsoft Defender XDR Unified role based access control (RBAC) (If Email & collaboration > Defender for Office 365 permissions is
Active. Affects the Defender portal only, not PowerShell): Authorization and settings/Security settings/Core Security settings (manage) or Authorization and settings/Security settings/Core Security settings (read).-
- Remove user accounts from the Restricted entities page: Membership in the Organization Management or Security Administrator role groups.
- Read-only access to the Restricted entities page: Membership in the Global Reader, Security Reader, or View-Only Organization Management role groups.
Microsoft Entra permissions: Membership in the Global Administrator*, Security Administrator, Global Reader, or Security Reader roles gives users the required permissions and permissions for other features in Microsoft 365.
Important
* Microsoft recommends that you use roles with the fewest permissions. Using lower permissioned accounts helps improve security for your organization. Global Administrator is a highly privileged role that should be limited to emergency scenarios when you can't use an existing role.
A sender exceeding the outbound email limits is an indicator of a compromised account. Before you follow the procedures in this article to remove a user from the Restricted entities page, be sure to follow the required steps to regain control of the account as described in Responding to a compromised email account in Office 365.
Remove a user from the Restricted entities page in the Microsoft Defender portal
In the Microsoft Defender portal at https://security.microsoft.com, go to Email & collaboration > Review > Restricted entities. Or, to go directly to the Restricted entities page, use https://security.microsoft.com/restrictedentities.
On the Restricted entities page, identify the user account to unblock. The Entity value is Mailbox.
Select a column header to sort by that column.
To change the list of entities from normal to compact spacing, select
Change list spacing to compact or normal, and then select 
Compact list.Use the
Search box and a corresponding value to find specific users.Select the user to unblock by selecting the check box for the entity, and then selecting the Unblock action that appears on the page.
In the Unblock user flyout that opens, read the details about the restricted account on the Overview page. Verify that you've gone through the suggestions in the Recommendations section to confirm that the account isn't compromised or to regain control of the account.
When you're finished on the Overview page, select Next.
On the Unblock user page, consider the recommendations and use the links in the Multi-factor authentication and Change password sections to Enable MFA and Reset the user's password if you haven't done these steps already. Enabling MFA and resetting the password are a good defense against future account compromise.
When you're finished on the Unblock user page, select Submit.
Select Yes in the warning dialog that opens.
Note
Under most circumstances, all restrictions should be removed from the user within one hour. Transient technical issues might cause a longer wait time, but the total wait should be no longer than 24 hours.
Verify the alert settings for restricted users
The default alert policy named User restricted from sending email automatically notifies admins when users are blocked from sending email. For more information about alert policies, see Alert policies in the Microsoft Defender portal.
Important
For alerts to work, audit logging must be turned on (it's on by default). To verify that audit logging is turned on or to turn it on, see Turn auditing on or off.
In the Microsoft Defender portal at https://security.microsoft.com, go to Email & collaboration > Policies & rules > Alert policy. Or, to go directly to the Alert policy page, use https://security.microsoft.com/alertpoliciesv2.
On the Alert policy page, find the alert named User restricted from sending email. You can sort the alerts by name, or use the
Search box to find the alert.Select the User restricted from sending email alert by clicking anywhere in the row other than the check box next to the name.
In the User restricted from sending email flyout that opens, verify or configure the following settings:
Status: Verify the alert is turned on
.Expand the Set your recipients section and verify the Recipients and Daily notification limit values.
To change the values, select
Edit recipient settings in the section or select
Edit policy at the top of the flyout.On the Decide if you want to notify people when this alert is triggered page of the wizard that opens, verify or change the following settings:
- Verify Opt-in for email notifications is selected.
- Email recipients: The default value is TenantAdmins group (Global Administrator members). To add more recipients, click in the empty area of the box. A list of recipients appears, and you can start typing a name to filter and select a recipient. Remove an existing recipient from the box by selecting
next to their name. - Daily notification limit: The default value is No limit.
When you're finished on the Decide if you want to notify people when this alert is triggered page, select Next.
On the Review your settings page, select Submit, and then select Done.
Back in the User restricted from sending email flyout, select
at the top of the flyout.
Use Exchange Online PowerShell to view and remove users from the Restricted entities page
To view this list of users that are restricted from sending email, run the following command in Exchange Online PowerShell:
Get-BlockedSenderAddress
To view details about a specific user, replace <emailaddress> with their email address and run the following command:
Get-BlockedSenderAddress -SenderAddress <emailaddress> | Format-List
For detailed syntax and parameter information, see Get-BlockedSenderAddress.
To remove a user from the Restricted users list, replace <emailaddress> with their email address and run the following command:
Remove-BlockedSenderAddress -SenderAddress <emailaddress>
For detailed syntax and parameter information, see Remove-BlockedSenderAddress.