Error: missing_credentials

What it means

The DeviceSDK API rejected the request because it could not find any of the three accepted authentication mechanisms:

A Authorization: Bearer <token> header - used by the dashboard and by direct API consumers.
A session cookie set by the dashboard login flow.
A dsdk_* CLI token - issued by devicesdk login and stored at ~/.devicesdk/credentials.json.

You’re calling the API directly without an auth header. Add Authorization: Bearer <token>. Get a token with devicesdk login (writes to ~/.devicesdk/credentials.json) or from your server’s dashboard Tokens page.
You’re running the CLI without logging in. Run devicesdk login (the CLI auto-discovers your server via mDNS) and re-try. If mDNS isn’t available on your network, run devicesdk login --host http://<server>:8080.
No server is configured. The host comes from (in order) DEVICESDK_API_URL, the --host flag, the host saved in ~/.devicesdk/credentials.json, or mDNS auto-discovery. If none resolves, log in first: devicesdk login.
Your script is running in CI without a token. Issue a token from your server’s dashboard and set DEVICESDK_TOKEN on the CI runner (point it at your server with DEVICESDK_API_URL).

invalid_token - the request did carry a token, but it didn’t match any account.
invalid_cli_token - same idea, scoped to CLI tokens.