Hi germanoma, Firefox doesn't have a built-in ad blocker, but the Enhanced Tracking Protection feature sometimes blocks the very same site because there's a close connection between tracking and advertising. Could you check: (A) Do you see a shield icon toward the left end of the address bar, near the lock icon? Click that shield icon to learn what Firefox may be blocking in the page and make an exception for the site. More info on managing the Tracking Protection feature in this article: [[Enhanced Tracking Protection in Firefox for desktop]] (before Firefox 70: [[Content Blocking]]). (B) Do you use any of these extensions: Adblock Plus, Blur, Disconnect, DuckDuckGo Privacy Essentials, Ghostery, NoScript, Privacy Badger, uBlock Origin or uMatrix Those and other content blocking extensions usually provide a toolbar button to manage blocked content in a page. There may or may not be a number on the icon indicating the number of blocked items; you may need to click the button to see what's going on and test whether you need to make an exception for this site. Any progress so far?