https://arstechnica.com/information-technology/2018/04/in-effort-to-shut-down-telegram-russia-blocks-amazon-google-network-addresses/

Early today, Roskomnadzor—Russia's Federal Service for Supervision of Communications, Information Technology and Mass Media—moved to enforce a new Russian federal law blocking the use of Telegram, the encrypted chat and social networking application that has become the favored tool of Russia's political opposition and journalists. The censorship began with Roskomnadzor instructing Internet service providers to block requests to Internet Protocol addresses of Telegram's servers.