I’m wanting to sell my old Apple Watch but it is not letting me erase to factory settings. It is not paired with any of my families iPhones yet it says it is. Help!

I can’t unlock my old Apple Watch because it is saying it’s paired with another phone. It is not paired to mine or my bf iPhone and we’re the only 2 that has used it. Has my bf name still in it but is no longer paired to his phone. I have tried to factory reseting it in its settings but doesn’t do anything when I push reset. Help!