Unable to Merge & send for sign collection - Error "Failed to send for collection. Internal error occurred in Zoho Sign."

Unable to Merge & send for sign collection - Error "Failed to send for collection. Internal error occurred in Zoho Sign."

Hello, 
We have been using Zoho CRM to create Contracts thru mail merge and then "Merge & send for sign collection", now we cant use it anymore, for some reason zoho sign creates a "Draft" of the document but never send it, what can we do to get back the signature collection? 
We did not change anything in any of zoho apps so we cant understand what is going on, is zoho writer broken? or is it zoho sign?