There is currently no way to access the pop-up blocker settings in Firefox for Android.
Under Advanced, tap Sites and downloads.Tap the Menu icon (three vertical lines).
How to Disable Pop-Up Blocker: iPhone/iOS
How to Disable Pop-Up Blocker: Safari (Mac)
To disable desktop notifications on Mac OS, follow the same steps as for Windows, above.
Make sure you have the latest version of the browser installed.