What is this https://ssl.facebook.com/roadblock/ thing that comes up, even when I'm using a VPN, and how do I?

I purchased a VPN so that I could get onto Facebook, and now it seems like there's a new obstacle... Does anyone know how I can get around it?|||Email you VPN provider and ask them about it. Your question doesn't make sense.|||Some more details would be helpful. Not enough information here.