Unable to create Contract using REST API

Summary:

I am trying to create a contract, contract line , contract party , Bill Plan and Revenue plan and wants to publish once complete. But I keep getting "You must complete required fields" which I use a POST operation. Could you take a look and let know if you find anything missing?

API - fscmRestApi/resources/11.13.18.05/contracts

Operation - POST

{
"OrgId": 300000062336249,
"ContractTypeId": 300000062484340,
"ContractNumber": "ABH_TEST",
"CurrencyCode": "USD",
"ContractParty": [
{
"PartyRoleCode": "CUSTOMER",
"PartyId": 300000062860960
},
{
"PartyRoleCode": "SUPPLIER",
"PartyId": 300000062336249
}
],
"ContractLine": [
{
"LineNumber": "LineNum",
"LineTypeId": 300000015563631,
"LineTypeName": "Free-Form, Project ",
"ItemNameTxt": "Testing"
}
],
"BillPlan": [
{
"MajorVersion": 1,
"BillMethodId": 12,
"BillMethodName": "Amount Based Invoice",
"BillPlanName": "Invoice Plan"
}
],
"RevenuePlan": [
{
"MajorVersion": 1,
"BillMethodId": 5,
"BillMethodName": "Amount Based Revenue",
"BillPlanName": "Revenue Plan"