That could be reported as a scam site so others Browser would also block that for their own Browser Security as well. This is across the board now just Firefox - they have to secure their own Browser from malware/virus and that could catch other nominal site but then you have to contact their site "webmasters" if such issues occurs to resolve those issues. Also if you have adblocker or blockers software that can also cause the issue as well so it's not just a Firefox or Browser issue as well.