According to  https://help.zoho.com/portal/community/topic/api-has-a-sandbox-environment the ZohoCRM Sandbox API can be accessed at  https://crmsandbox.zoho.com 

I am finding, however, that api calls made to this sandbox address returns an HTML document instead of the expected JSON response while the same request to https://accounts.zoho.com returns the proper response. Has the sandbox url changed or do I need to do additional configuration within CRM? I do have the sandbox activated.