ever since last week , i've noticed that many websites cannot be accessed , and it doesn't matter if i use firefox or chromium as a web browser .
as an example of such a website is:
all i get is a "Server not found" error page . sometimes after a few refreshes it works just fine .
i've checked it on a windows OS machine that is connected to the exact same LAN network , and the website is shown just fine .
i've also checked the /etc/hosts file and it doesn't contain anything suspicious .
what is going on? how can i fix it?