I'm attempting to debug this url however i get error constantly. why? http://summerburst.se/stockholm/

This is actually the error message I recieve:

{
   "error": {
      "message": "An unknown error has occurred.",
      "type": "OAuthException"
   }
}

Inside your website designs, there might be some restrictions to bots. You're obstructing Facebook bots which have demands for your site.

This link implies that how Facebook scraper sees your page.

You may also check detailed URL debug results on Facebook Object Debugger page