I've used it for years with immense gratitude. Then it stopped working. I use Firefox 56.0. When I tried to reinstall it gave "Download failed. Please check your connection." Workaround: install Disabled Add-on Fix for Firefox 47-56, then reinstall.
Thanks for reporting this! Can you let us know what URLs produce ads for you? Also what filter lists are you using? We will run a few test on our end and get back to you with a resolution. We look forward to your follow up!