Series 2 watch doesn't pair with iPhone 6s

I have an iPhone 6s whit the latest IOS and an apple watch I didnt use in years. Now that I wanted to use it when opened didnt pair with the phone so I sent the watch to factory settings.

Now when I try to pair it goes well until the point it asks my Apple ID associated with the watch. When I do this step it says that it's not a valid ID(its the only apple id I have and when I try to connect on my phone to the account it works). What am i doing wrong or what else can i do?

Thank you