Explain this error like I'm new to the stack

Help me find the root cause of this bug. Don't propose a fix until we've confirmed the cause.

What I expected: {{expected}}
What happened: {{actual}}
Steps to reproduce: {{steps}}
Error / logs:
```
{{error_output}}
```
Relevant code: {{code_or_files}}

Process:
1. List 3-5 plausible hypotheses, ranked by likelihood, each with the evidence for and against.
2. For the top hypothesis, give me the single quickest experiment (log line, breakpoint, command) to confirm or rule it out.
3. Wait for my result before continuing.

Help me find the root cause of this bug. Don't propose a fix until we've confirmed the cause. What I expected: {{expected}} What happened: {{actual}} Steps to reproduce: {{steps}} Error / logs: ``` {{error_output}} ``` Relevant code: {{code_or_files}} Process: 1. List 3-5 plausible hypotheses, ranked by likelihood, each with the evidence for and against. 2. For the top hypothesis, give me the single quickest experiment (log line, breakpoint, command) to confirm or rule it out. 3. Wait for my result before continuing.

Here is a stack trace from {{language}}:

```
{{stack_trace}}
```

1. Identify the frame where the error originates in MY code (not library code) and explain why that's the likely culprit.
2. Explain the chain of calls that led there.
3. List what information is missing to be sure (variable values, inputs).
4. Suggest the exact log statements to add, with file and line, to capture that information.

Here is a stack trace from {{language}}: ``` {{stack_trace}} ``` 1. Identify the frame where the error originates in MY code (not library code) and explain why that's the likely culprit. 2. Explain the chain of calls that led there. 3. List what information is missing to be sure (variable values, inputs). 4. Suggest the exact log statements to add, with file and line, to capture that information.

My app works locally but fails in {{environment}}.

Symptom: {{symptom}}
Local setup: {{local_setup}}
Production setup: {{prod_setup}}
Logs from production: {{logs}}

Walk through the usual local-vs-prod differences one by one (env vars, build mode, file paths and case sensitivity, network/CORS, timeouts, memory, dependency versions, time zones, permissions, caching/CDN) and for each say whether it fits my symptom and how to check it. Finish with the top 3 suspects.

My app works locally but fails in {{environment}}. Symptom: {{symptom}} Local setup: {{local_setup}} Production setup: {{prod_setup}} Logs from production: {{logs}} Walk through the usual local-vs-prod differences one by one (env vars, build mode, file paths and case sensitivity, network/CORS, timeouts, memory, dependency versions, time zones, permissions, caching/CDN) and for each say whether it fits my symptom and how to check it. Finish with the top 3 suspects.