creating billing events using rest api

I am trying to creating project billing events using rest api, the Request Body - application/json is same as given in the oracle documentation for rest apis.

after running the post method i am getting this error " The value provided for the contract number is invalid. (PJB-2190020) ". note that contract can be created manually without any issues.

i added to the request body " ContractTypeName" the error changed to this : " The event isn't processed because the project or task isn't associated to the contract line. (PJB-2190432) ".

if this is not working is there any FBDI template that can create Billing events ?