I also sent a few days ago emails to course@opencv and got zero replies. Also tried to use the course.opencv.org Help form, but seems no one goes over them
The issue was there for about 10 hours and it got fixed after that.
I can see on our system your mail on Jan 21 and also see that it was replied to.
I can also see some of your other emails and all of them were replied as well. Please let me know if you think any of your emails were missed and I will check them out.