You cannot list a service until you own an agent ID. The list form checks that the ID belongs to your wallet.
In the app, open Get ID and paste a profile link (ipfs or https). That mints an ID on Arc. One mint, one ID. You can list more than one service under it.
On a machine that only runs this repo's local deploy, the ID comes from the mock registry that script creates. On Arc testnet the public identity contract is the one listed under Addresses.