If apple watch won’t charge, there might be a problem with the charging cable, the magnetic charging dock, or the battery.
Checkout this video:
Check if apple watch is connected to its charger correctly. The charger must be plugged into a power outlet, and apple watch must be connected to the charger with the band open.
If you see a green lightning bolt icon on apple watch it means that apple watch is charging. If the icon is red, it means that apple watch has a low battery and needs to be charged.
If the charger or charging port on apple watch is damaged, see the Apple Watch Service page for more information.
If you’re using a third-party accessory or charger, make sure that it’s compatible with your Apple Watch.
