Sharing on Facebook doesn't work

I’ve had an occurring problem whenever I share articles on Facebook – most of them turn out saying just “Poplight | Poplight” in the title – however I would prefer it to be “[name of article] | Poplight”. How can I fix this?

And another problem that has occurred – whenever I try to share this article on Facebook: http://poplight.se/2015/02/21/jon-henrik-fjallgren-och-isa-till-final-i-melodifestivalen-2015/ – Nothing really happens. No “Preview” shows up.

I’m fairly a newbie on this and I couldn’t seem to find in any FAQ or documentation on how to solve this problem. I’ve tried running this through Debugger but there’s a lot of messages that pops up that I don’t really understand. (Yeah, I’m a rookie)

Thanks in advance for your help.

https://wordpress.org/plugins/nextgen-facebook/