Many users of Twitter found they had lost all their followers and people they were following.
Twitter’s status page acknowledged this and stated that some of its features are "intermittently" not available right now.
This included the ability to follow users, the users’ follow counts and the ability to send direct messages.
Twitter managed to recover the services within an hour of when they went down.
A similar issue happened in May, where the site was trying to fix a flaw which allowed people to force others to "follow" them on Twitter.
Twitter was forced to temporarily reset many accounts, making it seem like longstanding users had no followers or followings. It was restored shortly after.