My iPhone 11 Pro Max will not charge wirelessly.

Have you updated your phone to the most current iOS (13.3)? There was an update for this a couple updates ago. If you need to update, I'd recommend a Force Restart after the update. See this link for directions --> Force restart iPhone - Apple Support

Try this: https://support.apple.com/en-us/HT208078

also, are you using a thick case? If so it might block the charge.