Handle edge cases in notifications

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

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

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

Start by locating the notification and error-handling entry points under lib. The issue does not identify the edge cases, current messages, or expected wording, so clarify those requirements before making changes. Done should mean the agreed notification failures produce detailed, useful error messages and the relevant behavior is verified.

Written by the indexing model from the issue text.