Make sure the watch is charged up, connected to your phone with internet. If you press and hold the button, go to settings, scroll down to check for updates. By reset you have tried both rebooting and full factory reset?
Reboot: Touch the screen twice, then touch Settings > Reboot.
Factory Reset: Touch the screen twice, then touch Settings > Factory Reset.
Caution: Factory Reset clears all settings and information about the current paired phone, so you can pair your watch with a different phone.