This website loads an ad for downloading to Android which I don't have and it's a nuisance. I've tried blocking it without success. This ad loads before my home page and I have to close it before I can do anything else.
Does this occur on another browser on your mobile device? Can you try uninstalling Firefox then reinstalling it on your mobile device to see if it helps or not?
Firefox is my default browser and it's connected to that somehow. I have Yahoo as my homepage. This program showed up when I downloaded the latest version of Firefox.
Your homepage has nothing to do with Firefox being your default browser. Did you read the hyperlinked support page?
Can you attach a screenshot?
Use a compressed image type like PNG or JPG to save the screenshot.
So your home page setting is correct?
If you do not keep changes after a restart then see:
Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).