That has nothing to do with Firefox browser and Firefox browser doesn't send that message that comes from the site or malware installed doing that.

Can you tell whether the ads are part of the page? You can use an add-on like uBlock Origin to reduce in-page ads. (https://addons.mozilla.org/firefox/addon/ublock-origin/) If the ads are notification panels, either floating in the lower right corner or sent to the Windows alert center, you can check which sites have permission to show notifications and revoke the ones that shouldn't have it. In the following article, check the "How do I revoke Web Push permissions for a specific site?" section: [[Web Push notifications in Firefox]] A third possibility is that one of your existing add-ons is causing the problem. I'll provide general information on checking those below, but a quick test is to restart Firefox in its Troubleshoot Mode, which disables extensions automatically. See: [[Diagnose Firefox issues using Troubleshoot Mode]] (choose "Open" and not "Refresh" or "Reset" when given the choice). ---- You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either: * Click the puzzle piece button (Extensions button) on the toolbar > Manage extensions * Ctrl+Shift+a (Mac: Command+Shift+a) * "3-bar" menu button (or Tools menu) > Add-ons * type or paste '''about:addons''' in the address bar and press Enter/Return In the left column of the Add-ons page, click Extensions. On the right side, find the "Manage Your Extensions" heading. ''If there is at least one extension before the next heading -- "Recommended Extensions" -- please continue:'' Then cast a critical eye over the list below that heading. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything suspicious or that you just do not remember installing or why? If in doubt, disable (or remove). For your privacy and security, don't let mystery programs linger here. Any improvement? ''Note: Sometimes extensions can frustrate access to this page. In that case, first restart Firefox in its Troubleshot Mode and then try again.'' See: [[Diagnose Firefox issues using Troubleshoot Mode]] -- Open, not Refresh.