Test page centos hijack my facebook...

Hi

Every time I try to share on facebook (via post os simply sending a message to a friend) my website www.sickdogsurf.com it pops up the testing page of centos in the facebook preview (see here https://paste.pics/87d249c940f18ba132971173dfd811d0 ). I tried to fix this with official support, but it appears not to work...

Funny enough, if I share https://www.sickdogsurf.com , the testing page doesn't appear...

Support seems helpless, any idea?

Thanks a lot!!!
Roberto