“So in my testing doing 1) Whitelist by IP + 2) KB4’s recommended Inbound Gateway rule + 3) Disable Return Path header KnowBe4 Account setting; resolves all the banners. If you’re spoofing your own domain, you may also have to add KnowBe4s servers to your spf records.”
“We have been running KnowBe4 for a while now and have significantly reduced our phish prone percentage, but cannot imagine a case where its 100%. In all fairness, we have numerous users who are not savvy computer users and pretty much live on mobile devices only.”
“That being said KnowBe4 isn't a bad product if security budget has some money to be burned. However, if you are limited in budget, I'd spend it on different security products like better spam filter or upgrade to current one of have sandbox scanning.”