The Daily Mail and Mail on Sunday are the leading conservative newspapers in the UK and are known safe websites. I suspect they were wrongfully listed on Spam404 or Disconnect.me by someone who doesn’t like their politics. Please fix thankyou.
What version of the Browser and OS are you using? So far all reported blocks are from users with the old Muon based Brave.
It’s (likely per @Mattches) because you’re using an old (Muon based) version of the browser.
If you’re using the Muon based Brave, is there a reason you have to use the old version? If not, upgrading to the current release should fix your problem (your site opened fine in my current 0.63.14 Chromium: 73.0.3683.75 (Official Build) dev (64-bit) for MacOS 10.14.3).