Error Scenario Matrix

Build a comprehensive error scenario matrix for this feature.

FEATURE: [Description]
EXTERNAL DEPENDENCIES:
- [API 1]: [What it provides]
- [API 2]: [What it provides]
- [Database/service]: [What it stores]

USER INPUTS:
- [Input 1]: [Type, constraints]
- [Input 2]: [Type, constraints]

Generate a matrix:

| # | Error Scenario | Trigger | User Impact | Expected Behavior | AC (Given/When/Then) |
|---|----------------|---------|-------------|-------------------|---------------------|

Categories to cover:
1. Network errors (timeout, no connection, partial response)
2. Server errors (400, 401, 403, 404, 500, 503)
3. Validation errors (per input field)
4. Business logic errors (insufficient funds, limit reached, etc.)
5. Concurrency errors (stale data, conflict)
6. Unexpected data (malformed response, missing fields)