How to unblock your website on Facebook within 24 hours - unblock Facebook share

We recently noticed that one of our website was blocked by Facebook and we where not able to share any post on facebook.com and every time we tried to post on Facebook we used to get this message

After reading tones of post and Facebook Help Centre, it was not very clear what caused this block our website which is related to company didn't violate any Community Standards.

So our guess was that somebody maliciously reported our website as spam which resulted in block or it was false positive on Facebook side.

How did we resolve it & action taken from our side.

1. Step1 (didnt work): First thing we did was to report it to Facebook using the link "Let us Know" which showed on error message when sharing any post from our website. This was not of much help as Facebook doesn't reply quickly or at all based on the feedback i got from forums, blogs & Facebook forums it self. Step 1 could work if Facebook can't get back & resolve the issue as false positive.
2. Step 2 (this was not the issue): Cross checked website Meta Tag/HTML/Open Graph tags to make sure if they are inline with Facebook webmaster guideline which was also fine.
3. Step 3 (Worked): Verified Domain with Facebook solved the problem for us, Verify domain using file upload doesnt work so only way to verify domain was to Verify domain using DNS (TXT) Record. 

 After adding the new TXT Record i waited for about 4-6 hours for DNS changes to propagate and once i verified domain i was immediately able to share website pages on Facebook.

Steps to Verify Domain on Facebook and get unblocked by Facebook

• Step 1:  Create Facebook Business Account or Visit Business account if you have it https://business.facebook.com/settings
• Step 2:Goto Brand Safety  section and click on Domains
  
  
   
• Step 3: Add you domain
• Step 4: Verify your domain using DNS verification as HTML verification didn't work in our case
• Step 5: If you verified domain by adding DNS verification then wait for at-least 24 hours in our case we where able to verify after 4-6 hours as propagation was complete, Propagation may vary in your case.
  
• Step 6: Once DNS record is updated verify from Facebook as shown in Image below.

Note: This process worked for us and for the message we where getting, It may not work for other issue related to block. I recommend to take following action based on Facebook

Follow Facebook webmaster Guideline to make sure you are inline with Facebook https://developers.facebook.com/docs/sharing/webmasters/

Use Debugger tools for troubleshooting 
https://developers.facebook.com/tools/debug/sharing/
https://developers.facebook.com/tools/debug/og/object

Advise: Don't leave it to Facebook to resolve your issue if problem is on your side, As Facebook gets tones of requests everyday and its not possible for them to address every query.