To cut down on spam, Twitter cuts the number of accounts you can follow per day
https://techcrunch.com/2019/04/08/to-cut-down-on-spam-twitter-cuts-the-number-of-accounts-you-can-follow-per-day/
Twitter just took another big step to help boot spammers off its platform: it’s cutting the number of accounts Twitter users can follow, from 1,000 per day to just 400. The idea with the new limits is that it helps prevent spammers from rapidly growing their networks by following then unfollowing Twitter accounts in a “bulk, aggressive or indiscriminate manner” – something that’s a violation of the Twitter Rules.
Follow, unfollow, follow, unfollow. Who does that? Spammers. So we’re changing the number of accounts you can follow each day from 1,000 to 400. Don’t worry, you’ll be just fine.