Why don't most Linux Mint 18.3 KDE sites work?

Question

linux

for some reason, some sites prom, olx, ukr.net, sites with vacancies, etc. stopped loading.
I am the third day on this OS after Windows. Yesterday, when I went to bed, everything worked. Not today.
I have no idea what to do.

Answer 1

As an assumption (read, "wangyu"). Disable AdBlock.
Or, one more guess, since everything happened at night ... Call an exorcist and expel demons from the system unit, they apparently climbed the Internet at night and broke something.
In general, this question clearly needs to be thoroughly specified in this way.

Answer 2

If you live in Russia, then most likely Roskomnadzor banned them

Answer 3

mtu reduce