Not sure whether the following is relevant, as the issue is several months old now: Firefox 36 chang

Not sure whether the following is relevant, as the issue is several months old now:

Firefox 36 changed something that has an issue in this scenario: you are posting over HTTPS and the destination uses a CISCO ACE load balancer. See:

File Upload error with SSL

Upgrading from 35 to 36 caused secure connection failed errors

jquery - Firefox 36 aborts https requests with content length greater than 1778 - Stack Overflow