Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

You see "upstream connection refused" in your Nginx error log when proxying requests to p...

You run docker compose up and get an error like Error: Port 3306 is already al...

Fix Git SSL Certificate Problem: Unable to Get Local Issuer
You run git clone https://example.com/repo.git and get:
fatal: unable to acc...

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

Fix DNS Probe Finished NXDOMAIN for a Specific Website
If you see the error "DNS_PROBE_FINISHED_NXDOMAIN" in Chrome when trying to visit a speci...

Fix Nginx Upstream Connection Refused Behind Cloudflare
If you see upstream connection refused in your Nginx error logs while using Cloudfla...