Optimize auth for large datasets

**Problem**
When working with config, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

Locate the authentication and config error-handling entry points in the Shell project, then inspect how current failures are reported. Clarify which cases need more detail and consider existing checks around those paths; done means config-related authentication errors provide descriptive messages that support debugging.

Written by the indexing model from the issue text.