Unable to connect to Codecademy (html course)

After I have left my pc for 15 minutes and came back to resume the process - codecademy has disconnected and related issue appeared. I tried to relog, use different pc and internet, tried vpn, etc and nothing helped. Btw, the problem is only with this course, i have started CSS course and everething is fine. What should I do? Reset the course or just wait?

Many users could be doing the course at the same time as you, meaning there is no open port. Atm you just have to wait it out by doing another course or coding on your local machine.