gRPC

gRPC 2 UNKNOWN vs 16 UNAUTHENTICATED

Both gRPC 2 (UNKNOWN) and 16 (UNAUTHENTICATED) belong to the gRPC Status Codes category. 2 indicates that an unknown error occurred. This may be returned when a server raises an exception that doesn't map to any known gRPC status code. Meanwhile, 16 means that the request does not have valid authentication credentials for the operation.

Description

An unknown error occurred. This may be returned when a server raises an exception that doesn't map to any known gRPC status code.

When You See It

The server threw an unhandled exception or returned an error that gRPC couldn't classify into a more specific status code.

How to Fix

Check the server logs for the underlying exception. Wrap server-side errors with explicit gRPC status codes instead of letting them bubble up as UNKNOWN.

Description

The request does not have valid authentication credentials for the operation.

When You See It

No credentials were provided, or the provided token/certificate is expired or invalid. Different from PERMISSION_DENIED (code 7), which means authenticated but not authorized.

How to Fix

Provide valid authentication credentials (e.g., refresh the OAuth token, regenerate the API key, or renew the client certificate).

Key Differences

1.

gRPC 2: An unknown error occurred. This may be returned when a server raises an exception that doesn't map to any known gRPC status code.

2.

gRPC 16: The request does not have valid authentication credentials for the operation.

3.

You encounter 2 when the server threw an unhandled exception or returned an error that gRPC couldn't classify into a more specific status code.

4.

You encounter 16 when no credentials were provided, or the provided token/certificate is expired or invalid. Different from PERMISSION_DENIED (code 7), which means authenticated but not authorized.

When to Use Which

For 2 (UNKNOWN): Check the server logs for the underlying exception. Wrap server-side errors with explicit gRPC status codes instead of letting them bubble up as UNKNOWN. For 16 (UNAUTHENTICATED): Provide valid authentication credentials (e.g., refresh the OAuth token, regenerate the API key, or renew the client certificate).

Learn More