Apple watch series 3 won't pair with iPhone 11

Hi :) I've been trying to set up my Apple Watch S3 for my new iPhone. I erased everything on the watch. When I tried to pair it with the iPhone, they both were stuck at "Connecting to Apple Watch. This may take a moment". After some time, both devices go to the initial setup screen as if nothing has happened. Does anyone have an idea what might be the cause of this and how to fix it?