Apple HDMI adapter not charging my ipad

I have the official Apple Lightening to HDMI adapter (https://www.apple.com/shop/product/MD826AM/A/lightning-digital-av-adapter) , and have the Apple iPad charger plugged into the HDMI adapter along with my HDMI cable, but my iPad won't charge. If I plug the same charging cable directly into the iPad, it charges fine, but nothing when using the adapter. How do I fix this?