Why will my Apple watch not pair with my new phone?

I have the series 3 watch and I just purchased a new iPhone 11 yesterday. I traded my old phone in at the phone store so it is not in my possession anymore. When I got home my watch kept requesting to be connected to my new phone. Every time I try to connect my watch it will not allow me to. I have reset my watch back to factory settings and when I tried to update my watch it says update failed. I am confused if I am doing something wrong or if there is something wrong with my watch now.