Remove a Office 365 user from the Restricted users list

 https://security.microsoft.com/restrictedusers

Use the Microsoft 365 Defender portal to remove a user from the Restricted users list

In the Microsoft 365 Defender portal, go to (incidents & Alerts) Email & collaboration > Review > Restricted users.

On the Restricted users page, find and select the user that you want to unblock by clicking on the user.

Click the Unblock action that appears.

In the Unblock user flyout that appears, read the details about the restricted account. You should go through the recommendations to ensure you're taking the proper actions in case the account is compromised.

After you remove the user it needs 15 to 20 minutes to take effect.

When you're finished, click Next.

When you're finished, click Submit.

Click Yes to confirm the change.