@eric f11 Having pretty same problem here, trying to use contact search API, and getting not_found error code in the response, no matter what I'm sending.
Could you please explain what do you mean? I'm using version 2.3 (as I can see in developer-hub and still getting not found error: The requested resource does not exist; check your path and try again
UPD: Ok, I found it. Access token is bound to the specific application and its version must be up to date.