Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

If your site shows broken padlocks, mixed content warnings, or SSL errors after changing Cloudfla...

If you see PermissionError: [Errno 13] Permission denied while running pip ins...

Fix ERR_CERT_AUTHORITY_INVALID in Chrome Incognito Mode
You open Chrome incognito and hit a warning: NET::ERR_CERT_AUTHORITY_INVALID. Th...

Fix pip Externally Managed Environment Error on Linux
If you're seeing error: externally-managed-environment when trying to pip ...

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 Docker Build Context Canceled by Excluding Files
You run docker build and after a long wait see context canceled. This o...