Signing up for multiple Pinterest accounts

So I have a whole set of IP's, and I am trying to sign up for pinterest by connecting via these IP addresses. Unfortunatly everytime I try to sign up, I get stuck on a login screen. I sign up under different IP's, incognito mode, etc.. and it wont let me sign up a new account.

Anyone know what I could be doing wrong? I want to use seperate IP's to sign up for accounts.

Did you cleaned up your web browser cache with CCleaner or such?

Really? Simple connecting incognito or flushing the cache shouldnt do it?