The UBO guys have recommended turning off other plugins (obviously, start by turning off everything, then turn stuff on slowly until you find what is conflicting).
Oh, and make sure you're on Firefox, not any chromium based browser (Edge, Chrome, Opera, Brave etc).
I've also seen suggestions that you should try removing any custom filters (can't remember if that's direct from the UBO guys or not)
It worked for me but minutes later it started appearing again
The UBO guys have recommended turning off other plugins (obviously, start by turning off everything, then turn stuff on slowly until you find what is conflicting).
Oh, and make sure you're on Firefox, not any chromium based browser (Edge, Chrome, Opera, Brave etc).
I've also seen suggestions that you should try removing any custom filters (can't remember if that's direct from the UBO guys or not)
try this https://openuserjs.org/scripts/reek/Anti-Adblock_Killer_Reek