Errors

Common CLI and build error messages, their cause, and the fix.

Message	Cause and fix
`handler must default-export an object with fetch(request)`	The entry file has no `export default { fetch(...) }`.
`Node, Bun, and Deno APIs are not supported`	The handler or a dependency uses `process`, `Buffer`, `Bun`, `Deno`, or a Node built-in other than `node:path`, `node:url` and `node:querystring`. See Runtime compatibility.
`Proxy is not supported by the compiler`	This error comes from CLI versions before 0.16.0. Upgrade to use Porffor alpha-16 Proxy support; see Runtime compatibility for package-specific limits.
`fetch() refused: X resolves to <address>, a private or reserved address`	`fetch()` never reaches a private address. If the server’s operator means to allow it, they set `SB_EGRESS_ALLOW`; see Outbound fetch.
`unsupported config field: X`	`sproutboat.jsonc` has a field Sproutboat does not know. Check the spelling against the full shape.
`binding X: no resource <id>`	The config names a resource id you do not own. Create one with the product’s `create` command, such as `sproutboat kv create <name>`, or use a bare name and let deploy create it. See Storage resources.
`not serving after 90s`	The sprout is crashing, or Caddy is still issuing the certificate. Check `sproutboat tail --sprout`.
`X does not resolve to this server` (on `domains verify`)	Add the A or AAAA record, DNS-only, and re-run after DNS propagates. See Custom domains.
`deploy the project at least once before ...`	Secrets and custom domains need an existing deployment. Run `sproutboat deploy` first.