Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

If you see connect() failed (111: Connection refused) or connect() failed (13:...

Fix 'Permission Denied' When Deleting Files in VS Code
You try to delete a file or folder in VS Code's Explorer, but get an error: Permission ...

Chrome Certificate Error Invalid Authority: Diagnosis Checklist
When Chrome shows NET::ERR_CERT_AUTHORITY_INVALID and refuses to load a site, it...

Docker Compose Secret vs Environment Variable: When to Use Each
If you're writing a docker-compose.yml and wondering whether to put a value in <...

Fixing NGINX Upstream Connection Refused SSL Errors
When NGINX logs upstream connection refused for an SSL backend, it usually means the...

Docker Network Not Found But Exists: How to Fix
You run a Docker container and get an error like docker: Error response from daemon: networ...