Setting a lightning address on your profile is for receiving zaps and not for sending zaps. Looks like you have an NWC misconfigured with Amethyst. Maybe @Derek Ross can help you with that. I don’t use Amethyst much and couldn’t figure out where to access NWC settings. WoS does not support NWC so you probably have to reset your NWC settings so that you can have Amethyst prompt you to ask which wallet you want to zap with. When I click zap in Amethyst, it prompts me to ask which wallet I want to use. 

 I’d recommend checking out Primal. It’s way more noob friendly. Amethyst is more for advanced Nostr users. 

 That's great, thanks for your help. I'll send you a zap when I get it working 💪