555....I'm Canadian too and same due date. Mine went through yesterday after several attempts. I used Opera OS. Ensure you "Allow" pop-ups. I believe this is the last day the system will allow you report.
P.S. I had problems with entering nationality as well. List of nationalities would not appear.
I was having problems as well for a few days (and several months before) using IE and Chrome. Today, I switched my browser to Opera and worked like a charm:
1. Only fill out the area with an asterisk (*)
2. Turn off "Privacy Protection" at top right of screen.
3. Use ONLY drop down menu, where available.
4. ONLY, ONLY, ONLY fill out info with an asterisk. NOTE: address is two lines.
My November report at Promenada needed only passport and slip. Last week, needed passport, TM47, slip AND they noted my residence GPS coordinates on the TM47.
Same happened to me. Been doing it online for years then BOOM it stops working. No info whatsoever has changed. Tried 3 different browsers but still doesn't work. I've asked them but, of course, I get a blank stare.
I had been doing it online for years then suddenly it stopped worked. No information had changed and was doing nothing different. Did all the troubleshooting mentioned above several times but no luck. Been doing it in person last 3 times.