My Apple Watch does not pair with my phone

i have not connected my Apple Watch to my phone for more than 2 years

I am not sure what is my iPhone series but my phone is iPhone 8

when I start pairing it shows it pairs but then it ask to update the applewatch and when I click on update it provide and error message that you are not connected to internet

try again

start over

I tried manually to pair agin it pairs but we stuck on same place

how can I solve this problem ?