This problem appeared nearly one week ago. I tried to open the contest(after it had started) but I saw this plug
/predownloaded/65/66/6566176855d91cc58b8a9c51818c01b424a6fbe4.png
After this situation I opened codeforces from another browser. Just before the round everything was good and I could get everywhere here. Contest started and from this moment I was seeing only that plug(if I tried to get in round). As a consequence, now I can write cf rounds only using mirror.
So, till that moment I can open gym and all contest here, but I can't open any codeforces round and also main page.
Did anyone have the same problem? And if "Yes", how to solve it?
P.S. Sorry for poor english