Twitter is clamping down further on bot activity by reducing the number of accounts you can follow per day from 1,000 to 400. Verified accounts can still follow 1,000 per day.
Also, once the account reaches 5,000 follows, it will have to wait until it gains more followers before following any more accounts. It's not specific about the calculation to allow the accounts to start following again, and is variable depending upon the "unique ration of followers to following."
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