Why can't I follow anymore?
When Twitter says, "You're not allowed to follow anymore," Twitter doesn’t like your aggressive follow/unfollow churn, or you've used all your daily follow limits within the Twitter universe. When a user follows too many users in a short period or unfollows them, Twitter marks the user for a period to close-watch them for follows/unfollows across the Twitter ecosystem, including all 3rd party apps, Twitter mobile apps, and websites.
Since every Twitter account has a unique ratio between friends and followers, the ideal ratio may range from one account to another. This assessment is made automatically by Twitter depending on your account's specific balance.
If you don't seem to reach 5000 followers in near future, you may consider reducing your following number by eliminating some inactive and fake accounts you may follow, shown in the video tutorial below:
Or if you don't want to remove some accounts, you can make Twitter lists of your friends, and continue following them through these lists. Hence, you can continue following many other accounts without limiting yourself to 5000 following limit. We also got a hands-on video to enable you to create Twitter lists in bulk easily:
Twitter has its way of metrics to decide if you’re eligible to follow anyone on its connected platforms. You may hit your “account limitations” or "platform-based limitations” either together or individually. However, we're sure that once you hit the limit, Twitter eventually shuts you off for a certain amount of time to be sure you’re using Twitter within designated limits by them.
"What is aggressive follow churn? If you decide to follow someone and then change your mind later, you can visit the person’s profile page and unfollow them. Aggressive follow churn is when an account repeatedly follows and then unfollows a large number of Twitter accounts. That may be done to get lots of people to notice them, circumvent a Twitter limit, or change their follower-to-following ratio. These behaviors negatively impact the Twitter experience for other people, are common spam tactics, and may lead to account suspension. "
Twitter’s rules bind everyone
We suggest using tools with nonaggressive intent to strengthen your Twitter account(s).