Why do not all sites open via PPPoE?

Question

Computer networks

My router burned out, as a result, I temporarily plugged the cable into the computer (PPPoE). Under windows, everything worked as it should, but under Ubuntu and Fedora on three computers, some of the sites worked, some did not open at all (while pinging), and some were very stupid, for example, Fedora and Ubuntu turnips. A couple of days later I bought a new router and everything was fine. It doesn't seem to be a problem, but I'm just wondering what could be causing this? It reached insanity: the site of Leroy Merlin opens, but obi does not.