To unblock your website URL you need to visit Facebook debug page, enter your URL and write a few note to them. In this case Facebook reviews your application, your website URL and unblok it if they found no violation. In this case your Website URL may be unblocked and may not be unblocked, so make sure you write something that is heart pleasing to them.
This is an official Facebook unblocking link. Follow this link to unblock your website https://developers.facebook.com/tools/debug/sharingMind you Facebook will block your website URL if you spam or share your link in deceiving way. Always make sure you Abid by Facebook policy so you won’t get banned again.
Here’s is another method to share your link on Facebook even if your website URL has been banned.To avoid Facebook website ban it’s safer and better to always share your URL with shortener link. Shortened link helps to prevent face book ban. Let’s assume your website URL was banned on Facebook and you can’t share your website. The simple way to pass Facebook ban is by using shortener link. I recommend https://bitly.com but you can use any shortener link to share your website on Facebook.