It seems sometimes it may be a bit slow especially if one's computer isn't extremely powerful, but it should load after a few retries/refreshes. If all else fails you can probably just re-add the extension after removing it and it should work.

It doesn't work for maybe 30 minutes after contest ends. This is probably because the carrot extension has trouble connecting to the Codeforces API. It usually works an hour or so after. I don't think computer power matters, it is either: carrot works for everyone, or carrot can't connect, and it works for no one. However, it should be working now.