Fix Nginx 502 Bad Gateway Behind Cloudflare - How to Set Up the Laravel Artisan Command Path Environment Variable-Fix 'Could not get lock /var/lib/apt/lists/lock' on Ubuntu

Extra verification checklist

• Restart the affected app after changing permissions or configuration files.
• Test the same workflow in a clean browser profile or a temporary user account.
• Compare the result on another network if the error may be connection related.