University Twitter Account Follow Limit


Hi, I’m using Api 1.1 -> friendships/create for our University’s twitter account.

We are getting their twitter account names from students when they’re registering our university and my little php script follow all.

This is so organic way to communicate with students .

What am i doing wrong for twitter ? They are following back our account too, but twitter started to giving that error :
You are unable to follow more people at this time