The social media giant has also suspended the Twitter account of its new rival.
Twitter has blocked its users from sharing some links to its social media rival Mastodon.
Mastodon is divided into groups, called servers, based on many topics including the UK, snooker, and security.
Twitter has blocked links to some of the largest servers which users would join, including the most popular “social” channel.
And Twitter is also stopping users from adding links to their Mastodon account in their bios – calling them “malware”.
There is absolutely no evidence to support the suggestion that Mastodon contains malware – malicious software that can harm your device.
Mastodon said it gained hundreds of thousands of users in November, with some Twitter users seeking alternative platforms.
The BBC has been unable to post links to the most popular mastodon.social server, as well as more than 10 others – including a server for journalists and another for people in the UK.
But not all links to Mastodon have been blocked, and there are ways around it.
The BBC’s technology editor Zoe Kleinman was able to successfully tweet a reference to her Mastodon account – zsk@mastodonapp.
