Thank you for posting this in Microsoft Q&A.
I understand that you are experiencing an issue while configuring email notifications for alerts in Microsoft Defender for cloud. When you try to enter an email, you receive a privilege error, despite having the Global Admin role.
To configure email notifications in Microsoft Defender for Cloud, you require the Security Admin, Subscription Owner, or Contributor role.
Could you please verify the permissions you have on the subscription?
For your reference: https://learn.microsoft.com/en-us/azure/defender-for-cloud/configure-email-notifications#availability
Hope this helps. Do let us know if you any further queries.
Thanks,
Navya.
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