Hi,
Firefox had an issue today with expired certifications. They didn't intentionally ban Ad blockers.
A fix is already on the way and should be installed within the next couple of hours.
You can find more information about this here: https://blog.mozilla.org/addons/2019/05/04/update-regarding-add-ons-in-firefox/

If the issue however still exists past Sunday, please reach out to us via support@adblockplus.org!
Thanks,
Jessy
ABP Support Team