Website Unblocked: So this guide will only work if you are innocent. If your site has been blocked by Facebook and you believe it is a mistake, then this guide will show you how to appeal it.
More often than not, Facebook will unblock your website after 30 days or so if it is been flagged by an automated system.
As far as I know, permanent bands need to be issued by a human and they are less likely to make these kinds of mistakes.
Either way, mistakes happen and this is how you undo the issue.
Start by visiting the Facebook help site here. Scroll to the bottom of the page and you will see a section that says “find answers or contact support”.
you will need to follow the steps in this tutorial instead.
Scroll down through the page and click the options you need. You may be able to find the answer already here. If not, Facebook actually has a live support system and it is very good.
you scroll to the bottom of the page you will see the option to use the chat support. If the chat support is offline, or not available in your country, you can send an email.
When it happened to me, I had to send an email.
Facebook called me the next day to tell me that the domain block was a false positive and that the issue had now been resolved in their system.
So if you are innocent and believe an automated system has accidentally blocked your domain from Facebook.
this method of contacting Facebook will allow you to get its website unblocked very easily.
Writes- Yuzuho Hayashi, quora.