1) Scheduled time gaps (overnight is best example). 2) Unscheduled but controlled trading halts, e.g. because a company requests its stock to be halted pending a new information release. 3) Unintended interruptions due to tech stack problems anywhere from the exchange, to your broker, all the way to your own office (e.g. ISP or computer failure). 4) Too thin liquidity for your order size. Liquidity is inversely related to volatility, so "too volatile markets for your order size" would be another way of saying it. If you need guarantees, you can e.g. look into options that make defining exact risk very easy.
90% of stops will be hit sooner or later. You need to manage your position and get out before that happens, hopefully.
Probably shouldn’t trade in a volatile market anyway. My current rule is if I cannot comfortably put in a reasonable stop I won’t trade at all.
Exception being that you're trading during a liquidity crisis and the market is nosediving with the VIX going through the roof (circa 2008). In that case, having no stop loss will effectively blow up your account because price ain't coming back up for days, if not weeks.
BUT.... Having a stop loss will also drain your account in a volatile market, since there will be a lot of false triggers. Sometimes leaving you in a very bad position. With all the money you save in a volatile market on false triggers, you can afford to take a bigger loss. The bigger players also know where most retail stop losses are at and can use it against you. Instead of using stop losses I like to use the phone alert system that alerts me when a price has been triggered, this way I can judge whether to sell or buy, which is part of my strategy.