How do I find out why a website was blocked?

Here is how you find out why a website has been blocked:

1. Go the History page
2. Click on any "blocked" visit
   
   1.  You can filter results by clicking "Show Filters" and select a group, device, category, type, domain and date/time 
3. The details provide
   1. Why was this visit allowed
   2. What we know about the website
   3. What you can do about it