It is really devastating that Facebook will block your website URL and you will not be able to post anymore any links that is under that particular domain. Recently, this case happened to my website and I really do not know the reason why my website was blocked by Facebook.
I tried messaging them because there is an option there inside Facebook Support that will allow me to say my part to Facebook, but weeks have passed and there is no reply at all.
I read some Facebook threads regarding the same topic but most of the people with the same case as mine replied that Facebook will not answer the case at all. And for me that's given already, because who am I for Facebook to give some care about? Though someone replied there that a snail or traditional mail to the Facebook headquarter lifted his blocked website to the list, but, for my situation that will be a lot of time and effort and also for sure I will be consuming some money to make my mail reached Facebook. If only I am living in California, maybe this option will come in handy.
Well, to be able to know whether your website URL was already blocked by Facebook, the following issues while posting on your Facebook page occurs.
1. If Facebook already felt that your case is already becoming a little out of control and you are continuously posting links that is kinda dangerous or spammy, then they will warn you regarding your post.
A message saying: "This post goes against our Community Standards on spam." will automatically be seen on your Notification. You will also see there a message saying "Only you can see this post. If you request a review, we'll have someone take another look at the post". All I can say is do not wait because requesting a review is doable, but the review will take a very long time and you will come to you senses that Facebook is not viewing your case at all.
2. Now, if you tried to post a link on your Facebook page, if it was blocked already, then you may encounter the so called "Error in query" message, saying "Error in performing query."
3. If you tried to post your domain or website link using Facebook chat or message there will be a popup message coming from Facebook saying:
Your message couldn't be shared, because this link goes against our Community Standards. If you think this doesn't goes against our Community Standards let us know."
Even inside the chatbox, you will notice that the link you posted became color red and a warning message saying the same issue.
4. Some might think that using URL shorteners like bitly.com or tinyurl will work. But no! Not at all. I tried to shorten my blocked website URL and the same issue occurred.
5. Lastly, I tried the Sharing Debugger of Facebook that you can access here. I typed my website URL and pressed the Debug button....
...And it really saddened me, because it was confirmed that indeed my website URL was already blocked by Facebook. An alert message saying "We can't review this website because the content doesn't meet our Community Standards. If you think this is a mistake, please let us know.
I will also warn you that the so-called "please let us know" option will not also work even you will try to message them and say your side. No one will answer you from Facebook.
The only solution that you can do and will be very fast is buying another domain name, write articles the same as the blocked website. But now, be careful to share articles which are not spammy looking articles or articles which are dangerous when reviewed by Facebook. Since the data breached that happened on Facebook, they are now more strict in all the subjects that were shared on Facebook or maybe strict to those little websites only. I don't know.
If this also happened to you, please do not hesitate to share us your personal experience regarding the mentioned topic above. Sharing will also inform us about the actions that you take to maybe lift the blocking done by Facebook against your website.
Update as of May 5, 2019!!!
After almost 1 and 1/2 months the URL of my website that was blocked by Facebook was automatically unblocked by them. I can only say that the blocking is not permanent, but you just need to wait for Facebook to unblock your website URL.