Are you using a private window? Check for a "shield" icon at the left end of the address bar indicating that Firefox's Tracking Protection feature is blocking something. This article has more information on the icon and how to make an exception when you see it: What happened to Tracking Protection?.

Other than that, I don't think Firefox would be blocking any ads. Do you use Kaspersky or other security software that filters your web browsing?

I'm using FF 49.0 also. I went to this address "http://www.cbs.com/watch/" it played a 15 second ad in the video box just like youtube then continued to a 45 minute episode. Maybe try updating flash and java?

It appears to be Java blocking the ads. This is a fresh Win7 install and I do not recall installing Java. It is not listed in programs. How does FireFox and Java interact to block ads?

Here is the block: "u%5Fjava=true&ppos=1&u%5Fnmime=10&vpos=preroll&u%5Fnplug=7&lip=true&u%5Ftz=0&min%5Fad%5Fduration=0” was blocked because tracking protection is enabled."

Any help appreciated.

Note that the Java Plugin and the JavaScript in Firefox are two different things as JavaScript was originally going to be called LiveScript. http://kb.mozillazine.org/JavaScript_is_not_Java

Do you have any Extensions installed that can affect use of JavaScript like say NoScript?

I finally gave up and uninstalled FireFox. When I reinstalled FireFox, it somehow picked up bookmarks (and maybe attributes) from another system on my network. In any event, the problem appears to be solved. Thanks all for the help!

This is a response to james request for screen shots of the problem. The second image is the original issue. Note the block in the URL line, upper left. The 3rd image has the debugger displayed. The first image shows the problem can be solved by "allowing" the site on an individual basis. I was looking for a solution to turn off blockage universally for the web site. I now would like to just clear all remnants of Firefox from this computer and reinstall a clean version. This appears to only occur on this system when I run without Admin privileges. Also, on my other systems it is not an issue, even with only user rights. Thanks for any comments and help.

Hi bwsantana, the shield is generated by the Tracking Protection feature. There's no permanent site-by-site exception for that feature; it's only for the current session. If you prefer, you can turn that feature off completely using the steps in this article: What happened to Tracking Protection?.

Note: If you are not using automatic private browsing and tracking protection has gotten turned on in regular windows, there is a hidden setting for that:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste tracking and pause while the list is filtered

(3) If the privacy.trackingprotection.enabled preference is bolded and "user set" to true, double-click it to restore the default value of false

Note: The preference for tracking protection in private windows is: privacy.trackingprotection.pbmode.enabled and that does have a default value of true.

jscher2000: I checked privacy.trackingprotection.enabled and it is set to false. I am not trying to use private browsing on purpose. privacy.trackingprotection.pbmode.enabled was set to true by default and I set it to false.

bwsantana said

jscher2000: I checked privacy.trackingprotection.enabled and it is set to false. I am not trying to use private browsing on purpose. privacy.trackingprotection.pbmode.enabled was set to true by default and I set it to false.

That should take care of it.

Setting the value to false appears to have solved the problem! Thank you.