403 Forbidden

Hello

I am trying to create a lead using the following information

https://mktorest.com/POST/rest/v1/leads.json?access_token=xxxxxxxxxxxxxxxxxxxxxxxxxxx

Payload

{ 

   "action":"createOnly",

   "lookupField":"email",

   "input":[ 

      { 

         "email":"kjashaedd-1@klooblept.com",

         "firstName":"Kataldar-1",

         "postalCode":"04828"

      }

   ]

}

But when i execute the request. I get the following error

<html> <head><title>403 Forbidden</title></head> <body bgcolor="white"> <center><h1>403 Forbidden</h1></center> <hr><center>nginx</center> </body> </html>

Please advise

Ashwini