I see your problem by opening your profile on Amethyst.. you set a LN Invoice as your LN Address, a LN Address should look like an email, like: thisisanexample@walletofsatoshi.com.
As of right now you can only get one of these by either hosting your own LN node + LN Address webserver, or using a custodial LN wallet like Wallet of Satoshi, where they give you one.
This is one of the main problems with zaps today cause the easy way is to use a custodial wallet like WoS.
You can find a list of LN Address providers here:

The Lightning Address
Like an email address, but for your Bitcoin. An Internet Identifier that allows anyone to send you Bitcoin instantly over the Lightning Network. No...
Usually people on Nostr use Wallet of Satoshi, Alby, ZBD LN Addresses.
So all you need is to install one of those wallets, copy the LNAddress, the one that looks like an email, and paste it where you pasted the LN Invoice before. Cheers! π€