Systematic Debugging

I'm debugging a {{language}} issue in a {{framework}} app.

**Symptom:** {{describe what's happening}}
**Expected:** {{describe what should happen}}
**Environment:** {{dev/staging/prod, OS, versions}}

**Error message (if any):**
\`\`\`
{{paste error}}
\`\`\`

**Relevant code:**
\`\`\`
{{paste code}}
\`\`\`

**What I've tried:**
- {{attempt 1}}
- {{attempt 2}}

Walk me through debugging this systematically:
1. What are the most likely root causes? (ranked by probability)
2. How to confirm which cause it is (specific commands or logs to check)
3. The fix for each possible cause