Usually ad blocking add-ons will provide a toolbar button to make site exceptions, or manage them in other ways. When you first install the ad blocker, its button is likely to be on the drop-down from the Extensions button. Can you find it there: [[Manage your extensions using the extensions button in the toolbar]]. If you do not have an add-on blocking ads, maybe the site is complaining about the Tracking Protection feature? When needed, you can make a site exception by clicking the shield icon at the left end of the address bar -- next to the lock -- and then clicking the slider switch to turn off Tracking Protection on the current site. Do either of those resolve the issue? If not, could you describe the problem in more detail.