I am new to Zoho API. Using the API documentation, I was able to create a TokenAuth and fetch the list of the first set of Contacts in our account using the following API call:

https://crm.zoho.com/crm/private/json/Contacts/getRecords?authtoken=TOKEN&scope=crmapi

This gives me the first 20 records. Now I want to fetch the next 20, so I tried the following:

https://crm.zoho.com/crm/private/json/Contacts/getRecords?authtoken=TOKEN&scope=crmapi&fromIndex=20

Unfortunately this does not seem to be working. Can anyone explain why? My goal is to sync the Contacts in our Account with an external system by fetching them in this manner. 

If there is another way to get ALL Contacts in our account in one shot please let me know that as well. 

Thanks!