{"message":"The Customer field can neither be blank nor be incorrect. Please enter a correct customer.","code":3008}

{"message":"The Customer field can neither be blank nor be incorrect. Please enter a correct customer.","code":3008}

My first time trying to create an estimate (through Books) from within CRM using a custom function and running into issues.

I am receiving the following message when I hardcode the customer_id into the request:

{"message":"The Customer field can neither be blank nor be incorrect. Please enter a correct customer.","code":3008}


Here is the request line:

newEst = zoho.invoice.create("Estimates",OrgID, {"customer_Id": "591106000000340027", "line_items": [ { "item_id": "591106000000376037", "name": "Something", "rate": "10.00"  } ] });

Thank you.