Zoho sheet download "internal server error message" (recently started)

Zoho sheet download "internal server error message" (recently started)

Hi Zoho team,

For Zoho Sheet API code that has been working unmodified for a year, I recently started getting the error message: " Internal Server Error while processing this request". 

This error occurs even when I cut and paste the https GET request into a chrome browser address bar, and therefore seems to be unrelated to my code.

This worked for a year until Monday 11/05/12, but has not been working since Tuesday 11/06/12) .

The actual request is:
 
https://sheet.zoho.com/api/PRIVATE/xls/download/XXXXX?apikey=XXXXXXXXXXXX&ticket=XXXXXX
 
(where document ID, API Key and ticket have been masked for privacy).

Please look into this as the application I am working on depends on this Zoho API working correctly all the time.

Thanks,
-James