I am trying to delete the record from the annotation entity using the portal API below but it doesn't allow me from the portal.
https://docs.microsoft.com/en-us/power-apps/maker/portals/write-update-delete-operations
I have all privileged setup for annotations table like create, update, delete but still, it doesn't allow me to delete the record from annotation entity.
Do I need to do anything else?
You will probably get a better response if you show your actual code that you are trying, rather than just linking to Web API page.
Also, look for any errors being returned in the Browser's (F12) Console or Network traffic