Eureka! I found something that fixes the problem: https://developers.facebook.com/tools/debug
I enter the URL here, click ‘DEBUG’ and for some reason it “cleans” the URL. Once that’s done, I go back to my fan page, post the link and voila, it works!
I have no idea why this works, but it does. And BPS is active.
Thanks a lot for all your help!
