Checklists for software errors, setup, and tool workflows.

How to Fix Nginx Upstream Connection Refused on Port 80

When nginx logs show "upstream connection refused" while connecting to port 80, it means ...

Fix Nginx Permission Denied for Static Files

Common Causes

When Nginx returns a 403 Forbidden or 'permission denied' error for...

Docker Prune Not Freeing Enough Space: Practical Fixes

You run docker system prune -a expecting a big space recovery, but the freed space i...

How to Reset Windows Defender Real-Time Protection

Windows Defender real-time protection can sometimes get stuck, fail to turn on, or stop respondin...

How to Fix Nginx Redirect Loop from HTTP to HTTPS

If you're seeing an infinite redirect loop when trying to force HTTPS in nginx, the browser u...

Firefox Secure Connection Failed: Date and Time Fix

If you see a 'Secure Connection Failed' error in Firefox that mentions date or time, it u...