Today, I was trying to solve some problems on Trie. I was following a list of problems on this topic. It has some problems from codeforces as well. Two of them were 706D - Vasiliy's Multiset and 665E - Beautiful Subarrays. When I tried to access the first problem, an error message popped up like this:

Oops! Probably Codeforces can't be reached right now or your Internet connection is broken. You can try:

reload the page return to the main page visit official mirror website mirror.codeforces.com visit m1.codeforces.com, m2.codeforces.com or m3.codeforces.com (if you are taking part in the official round right now)

I thought codeforces was down. But then when I clicked on the link to the second problem, it loaded normally. Then I go to the Problemset section of codeforces and try to view a random problem like 501A - Contest. The same error message popped up. Any idea why this is happening? I am kind of confused.

Edit: The problem is resolved now.