Hi RJ, the ad blocker accusation indicates that some aspect of the site didn't run as expected, and the site is guessing the possible reason. If it's inside Firefox -- not caused by external security software/services -- here are the things to check:

(A) Firefox's Tracking Protection feature: The shield icon toward the left end of the address bar usually turns a bit purplish when content is blocked. Click the icon to learn more or make an exception. See: Enhanced Tracking Protection in Firefox for desktop.

(B) Extensions: Adblock Plus tells you what it is, what many others may block ads: Blur, Disconnect, DuckDuckGo Privacy Essentials, Ghostery, NoScript, Privacy Badger, uBlock Origin or uMatrix, for example.

Usually you can find a toolbar button for each add-on to manage blocked content in a page. If it's not directly on the toolbar, check the Extensions button (puzzle piece button) drop-down list. See: Manage your extensions using the extensions button in the toolbar.

There may or may not be a number on the icon indicating the number of blocked items; you sometimes need to click the button to see what's going on and test whether you need to make an exception for this site.

tks very much for your helpful answer, I am now able to read all the news I want. The *Firefox's Tracking Protection feature* was ON, I turned if OFF for the sites I needed to read