Any tips for nighttime potty training?

Dayna

My 4y/o has been daytime potty trained since he was 2 but can’t seem to hold it at night. We have tried limiting liquids at night and taking away the pull-ups, but he still has accidents 3-5 times a week. He doesn’t wake up when it happens, just sleeps in it. He sleeps like a rock, which is normally a good thing, but I’m not sure how to get him potty trained at night.