Getting Error -4016

Getting Error -4016

Hello 
I am trying to create and invoice in zohobooks via api
I am getting Error code - 4016 
Message - please select an item 

Code 
"item_id"= "1156676000001650000","product_type"= "SERVICES","hsn_or_sac"= "998315","name"= "HOSTING", "description"= "500GB, USB 2.0 interface 1400 rpm, protective hard case.","item_order"= "1","bcy_rate"= "120","rate"= "120","quantity"= "1","unit"= " 1","tax_name"= "GST18","tax_percentage"="18"

I dont understand whats missing