C98EFXN670HRVH8W3C5AF1D1AS-excl-cloud.mail.protection.outlook.com AXFR zone transfer

Not an apex domain The domain C98EFXN670HRVH8W3C5AF1D1AS-excl-cloud.mail.protection.outlook.com is not the root of its zone.
Instead, try zone transfer on mail.protection.outlook.com .