Using Repository Dispatch API gives me error

Hey guys, I followed lot of documents for this and tried different combination but I still get
{

"message": "Not Found",

"documentation_url": "https://docs.github.com/rest/reference/repos#create-a-repository-dispatch-event"

}

In my Postman when I try to POST my repo api, and the workflow never gets triggered what is it that am I missing?
Followed -

and many more but still the same outcome… need Help !!