I was using site_id in firebase.json

{
  "functions": { "source": ".output/server",
    "runtime": "nodejs22"
  },
  "hosting": [
    {
      "site": "site-id-123",
      "public": ".output/public",
      "cleanUrls": true,
      "rewrites": [{ "source": "**", "function": "server" }]
    }
  ]
}

but site was not created. I created it by runnig: firebase hosting:sites:create SITE_ID

https://firebase.google.com/docs/hosting/multisites#add_additional_sites