Not able to submit my code in September Challenge - SEPT17

@admin: I am trying to submit my solution to the problem “Fill The Matrix” (FILLMTR), since morning, but each time I made my submission it says “403 Forbidden”.
Even the submission is not shown in my Recent Activities or in the problem submission status.
I am experiencing this problem but I can see others’ status of compilation on same problem.
What am I supposed to do now? Please help me out.