Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

When you see fatal: unable to access 'https://...': SSL certificate problem: unable...

Fix Nginx Upstream Connection Refused in Docker
You have Nginx running, either on the host or in a container, proxying to another Docker containe...

Fix DNS Probe Finished NXDOMAIN on Chrome for Android
If you see the error 'DNS_PROBE_FINISHED_NXDOMAIN' in Chrome on your Android phone, it me...

Fix Nginx Upstream Connection Refused Socket Error
When Nginx returns a 502 Bad Gateway or logs upstream connection refused

Common Causes of Nginx Configuration Test Failure
When you run nginx -t and see an error, it usually means a syntax mistake, a missing...

Fix npm run build Failure from Missing Env Variables
You run npm run build and get an error like Error: Missing required environmen...