Is it normal for potty training to suddenly go backwards?

For context, I have a 4-month-old French Bulldog, and I’ve had him for about 6 weeks now. He was actually doing really well with potty training, going outside most of the time and barely having accidents. But over the past few days, he’s suddenly started having accidents inside again, even shortly after being taken out. Nothing really changed in our routine, which is why I’m confused. It feels like we’re going backwards I’m not sure if this is just a normal regression phase or if I’m doing something wrong without realizing. Did your puppies go through something like this too? And what helped you get back on track?