Getting values from Zoho Invoice in a Formula Field - NOT WORKING

Getting values from Zoho Invoice in a Formula Field - NOT WORKING

Here is what I have:
  1. A formula field on the form that calls a function, The function accepts the ID field of the form as the parameter.
  2. The function makes a call to Zoho Invoice Get Invoice Item API (https://invoice.zoho.com/api/items/)
The function works perfectly when tested independently for the same ID values that the formula field would have passed in. However, the view on this form which has this formula field as a column, does not display any value.

Regards
Moiz Tankiwala
Smart Training & IT Solutions