Why my Apple Watch won’t connect to Wi-Fi after unpairing?

My Apple Watch was unpaired now when pairing it won’t connect to the internet so won’t run updates, it won’t even tell the time it just keeps taking me through the same set up steps and then telling me it can’t update because it’s not connected to the internet. It’s only 18 months old and I loved it! I’m so frustrated. Please help.

[Re-Titled by Moderator]