Charging is not supported with this accessory

Hi,

It's ok. Same thing happens when I place my iPhone on the charger I purchased directly from Apple. Just ignore it.

What you can do is send feedback to Apple > http://www.apple.com/feedback/watch.html

You can also report the issue directly to Apple on Twitter: @AppleSupport

Hi

When charging your watch, check that:

All plastic wrap has been removed from both ends and both sides of the charging cable (check closely on the head).

• The back of your watch and the head of the charging cable are clean and dry:

  Clean them with a nonabrasive, lint-free cloth.

• The charging head is properly aligned with the back of the watch, with the concave / curved side touching it fully:

  Some watch docks, stands, cases or protectors might hinder this.

• In addition to using the Apple-supplied cable, if you are charging your watch by plugging into mains power:
  • Check that the USB connector on the charging cable is pushed fully into the USB Power Adapter.
  • Check that the adapter is fully pushed into the power outlet.
  • Use only adapters from the following:
    • The genuine Apple USB Power Adapter that was supplied with the watch, or;
    • A genuine Apple 5W (iPhone) or 12W (iPad) adapter, or;
    • An Apple-certified (MFi) third-party 5W adapter.
  • Try testing with another suitable alternative adapter or instead charging via a USB port.
• If charging via a USB port on a computer, ensure that you use a USB 2.0 or 3.0 port, the computer remains turned on and awake and the cable is plugged directly into the computer (not into, for example, an external keyboard).

If your watch still displays the error message, try force restarting it: press and hold both buttons for around 10 seconds, until the Apple logo appears.

More information:

Check your battery and charge your Apple Watch - Apple Support

If your Apple Watch won't charge or it won't turn on - Apple Support