I believe the biggest danger in opening the incubator is while they are in the process of hatching - it could cause the membrane to dry out. If none of them have pipped, I think you’re OK if you don’t leave it open too long. It wouldn’t hurt to candle a few of them. If no movement, I would give it another day or so before calling it. It can take 24 hours or more after rocking before they pip. Sometimes if you listen very carefully you a hear faint chirps.
It could be that your temperature was a bit low, causing a delayed hatch. The thermometers built into the incubators are notorious for being incorrect.