I’ve just solved the problem!
The problem (Response Code 206) occurs because of this WordPress plugin: WP Super Cache. When you activated it, it creates caching codes (rewrite modules) into htaccess file. Just delete the WP Super Cache caching modules from htaccess, and if you need that codes, you can create it manually. After I deleted the codes from htaccess file, everything is working fine and no more 206 errors. When I share a URL from my website in Facebook, image, title and description now shows perfectly.
I hope it would help who gets the same error.