Can't create a ticket via API

Can't create a ticket via API

Hello,

I am using a post service (Servistate on Chrome extensions) to quick test creating a ticket via Zoho Desk API before writing code.
I am sending a POST request to https://desk.zoho.com/api/v1/tickets
with correct authorization and orgID (They work because I tried other get/post requests successfully like retrieving customer ID, and search for customer via email)

I also provided the three required parameters: subject, departmentId & contactId as mentioned in the documentation here https://desk.zoho.com/DeskAPIDocument#Tickets#Tickets_Createaticket

I am getting a Status 400 Response, see attached screenshot

What am I missing? 

Thank you!