On April 16, 2018, the Russian government began blocking access to Telegram, an instant messaging service. The blocking led to interruptions in the operation of many third-party services, but practically did not affect the availability of Telegram in Russia. It was officially unblocked on June 19, 2020
Some say it was unblocked because they made a deal with Durov. Another opinion is that too many people and services including officials continued to rely on it even during the time it was blocked. Regardless, Telegram did a huge job on circumventing those blocks.