Moodle 2.4.1 and RM Network Students with Internet ban can't submit assignments

[CarolBooth]

I am really struggling to work out what is happening!

Our moodle is hosted on site and assignments work perfectly well if our internet connection is down but students who have an internet ban in the RM Managment Console can do everything in moodle other than upload a file.

Is there a technology that the internet ban is blocking? how can this be???

thanks

Carol