I have 3 Pan Cams and I have to power cycle each of them if I power cycle my modem/router. All other cams reconnect without doing anything.
My experience is that it takes a while sometimes. Give it overnight.
How long do you give the cameras to connect? As @K6CCC said, it can take longer sometimes. The most I’ve waited is 5 hours, the cameras were in a remote location that I couldn’t access quickly.
Also, is there any settings on your router that may cause this?
I’ve never had issues with my ASUS gear.