Sounds similar to this thread where an external script or ad blocker (McAfee) was causing the issue: I am currently blocked from using a website because it states my browser has ad blocking software. Can someone tell me what steps I need to take rectify this?

If that isn't relevant... to see whether any of your extensions are a factor, you could try Firefox's Safe Mode. That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?

Hi lzachau,

The website is probably telling you to disable or add an exception to Firefox's built in pop up blocker.

You need to make an exception for that website. To do that, go to Pop-up blocker settings, exceptions and troubleshooting and click the link that says Is the pop-up blocker on and enabled for this site? to add the exception.

If it doesn't help, don't hesitate to reply!