We tested zaps on this note… we made six attempts to⚡zap this note, at user13823331@fountain.fm, over a period of about 1 hour. In each case, we found that your lightning address server did not respond correctly. (The failure point was when we did a GET request to your specified callback URL: https://api.fountain.fm/v1/lnurlp/user13823331/pay ). Your server did not produce an invoice, thus the zap failed. The error we got was "zap request". You might want to look into using a cloud-based Lightning node which is optimized for Nostr zaps, to get your zaps working.