Paypal cannot complete transaction

I apologize for re-posting but my question was never answered. I have only one payment gateway selected and that is the paypal single payment gateway. After I click on subscribe, it takes me to the checkout page where it asks me to log into paypal. After I enter in my credentials, I am taken to a page where it says "Sorry - your last action cannot be completed". And it goes on to tell you what to do.

I went back to my site to re-subscribe but I keep getting the same message over and over again. I've already cleared my cache. Why can't Paypal complete my subscription?