Optimize config for large datasets

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

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

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

The issue names no files, tests, or entry points, and its title does not match the authentication request. Start by locating the authentication error-handling path and checking existing messages and tests. Done means the relevant authentication failures produce more descriptive messages and the behavior is covered by tests.

Written by the indexing model from the issue text.