Don't have Telegram yet? Try it now!
https://nishantrana.me/2021/01/22/export-key-attribute-uniquename-for-component-customapi-must-start-with-a-valid-customization-prefix-exception-while-creating-custom-action-in-dynamics-365/
Export key attribute uniquename for component CustomAPI must start with a valid customization prefix exception while creating Custom Action in Dynamics 365