If Yandex.Browser informs you that a social network site is not available, try opening this site using a different browser. If the error is repeated there, access to the site is most likely blocked by a program such as a firewall or antivirus. Certain viruses can also block access to a site.
If you see a page asking you to enter your phone number instead of the social network site, you have probably encountered a virus.
For more information, see the section Phishing .