Getting error "Security Constraints prevent ordering of item" while using post operation on a item

[Aparajita_ACN]

I have a catalog item which is inside an order guide. If I am using POST operation directly on the catalog item, I am getting error as "Security Constraints prevent ordering of item" (400 bad request).

[Ankur Bawiskar]

@Aparajita_ACN 

are you sure you are sending the correct json request body?