Clue: The domain loads, but it shows a parked or default registrar page instead of your static site.	Likely diagnosis: The request is not consistently reaching the intended VPS for that hostname.	topicladder vps debugging lab
First command for Domain still shows the registrar parking page	dig +short example.com A	topicladder vps debugging lab
Expected output for Domain still shows the registrar parking page	DNS returns a registrar, parking, or old hosting IP, or the direct Host-header check reaches different content than the domain.	topicladder vps debugging lab
Fix checklist for Domain still shows the registrar parking page	Correct the A record for the exact hostname.; Record the resolver answer before changing another record.; Retest HTTP only after DNS returns the intended IP.	topicladder vps debugging lab
Second verification command for Domain still shows the registrar parking page	dig +short @1.1.1.1 example.com A	topicladder vps debugging lab
What not to do for Domain still shows the registrar parking page	Do not jump to broad edits before the inspection command proves the failing layer.	topicladder vps debugging lab
Clue: https://www.example.com loads, but https://example.com does not, or the reverse happens.	Likely diagnosis: The root and www hostnames are not configured as one intentional pair.	topicladder vps debugging lab
First command for www works but the root domain fails	dig +short www.example.com A	topicladder vps debugging lab
Expected output for www works but the root domain fails	One hostname resolves or redirects correctly while the other is missing, stale, or routed differently.	topicladder vps debugging lab
Fix checklist for www works but the root domain fails	Choose the canonical hostname.; Add or correct the missing record.; Verify both hostnames and their redirect behavior.	topicladder vps debugging lab
Second verification command for www works but the root domain fails	dig +short example.com A	topicladder vps debugging lab
What not to do for www works but the root domain fails	Do not jump to broad edits before the inspection command proves the failing layer.	topicladder vps debugging lab
Clue: http://example.com returns a response, but https://example.com shows a certificate or connection failure.	Likely diagnosis: The web route exists, but certificate coverage or TLS routing is not correct yet.	topicladder vps debugging lab
First command for HTTPS fails after HTTP starts working	curl -I http://example.com	topicladder vps debugging lab
Expected output for HTTPS fails after HTTP starts working	HTTP reaches the server, but HTTPS shows a missing, wrong, expired, or unmatched certificate.	topicladder vps debugging lab
Fix checklist for HTTPS fails after HTTP starts working	Confirm DNS and HTTP first.; Check certificate names and expiry.; Fix the TLS server block or request the right certificate once prerequisites are true.	topicladder vps debugging lab
Second verification command for HTTPS fails after HTTP starts working	curl -I https://example.com	topicladder vps debugging lab
What not to do for HTTPS fails after HTTP starts working	Do not jump to broad edits before the inspection command proves the failing layer.	topicladder vps debugging lab
Clue: The browser reaches Nginx, but it shows the default welcome page instead of your project.	Likely diagnosis: The request reaches Nginx but falls through to the wrong server block or document root.	topicladder vps debugging lab
First command for Nginx default page appears	sudo nginx -t	topicladder vps debugging lab
Expected output for Nginx default page appears	Nginx is alive, but the matching server block or root path does not select your release.	topicladder vps debugging lab
Fix checklist for Nginx default page appears	Fix the intended server_name/listen/root block.; Run nginx -t before reload.; Retest with the Host header and the public domain.	topicladder vps debugging lab
Second verification command for Nginx default page appears	systemctl status nginx --no-pager	topicladder vps debugging lab
What not to do for Nginx default page appears	Do not jump to broad edits before the inspection command proves the failing layer.	topicladder vps debugging lab
Clue: The route exists, but Nginx returns 403 when loading the static site.	Likely diagnosis: Nginx found the path but cannot traverse or read the file as the service user.	topicladder vps debugging lab
First command for 403 forbidden after deploy	namei -l /srv/www/example.com/current/index.html	topicladder vps debugging lab
Expected output for 403 forbidden after deploy	A parent directory lacks execute permission, the file is unreadable, or Nginx logs name a permission issue.	topicladder vps debugging lab
Fix checklist for 403 forbidden after deploy	Fix the specific path component shown by namei.; Avoid broad recursive permission edits.; Retest after the smallest owner or mode correction.	topicladder vps debugging lab
Second verification command for 403 forbidden after deploy	stat -c '%A %U:%G %n' /srv/www/example.com/current/index.html	topicladder vps debugging lab
What not to do for 403 forbidden after deploy	Do not jump to broad edits before the inspection command proves the failing layer.	topicladder vps debugging lab
Clue: The domain loads but a page that should exist returns 404.	Likely diagnosis: The web server is responding, but the requested path does not map to a generated file in the active release.	topicladder vps debugging lab
First command for 404 after a fresh deploy	find /srv/www/example.com/current -maxdepth 2 -type f | sort | head -50	topicladder vps debugging lab
Expected output for 404 after a fresh deploy	The generated file is missing, the URL path differs, or Nginx points at a release without that file.	topicladder vps debugging lab
Fix checklist for 404 after a fresh deploy	Confirm the file exists in the current release.; Regenerate or deploy the missing route.; Retest the exact URL path.	topicladder vps debugging lab
Second verification command for 404 after a fresh deploy	readlink -f /srv/www/example.com/current	topicladder vps debugging lab
What not to do for 404 after a fresh deploy	Do not jump to broad edits before the inspection command proves the failing layer.	topicladder vps debugging lab
Clue: You deployed new content, but the live page still shows old text or an old asset version.	Likely diagnosis: The deploy artifact exists, but the live symlink, cache, or generated asset reference is stale.	topicladder vps debugging lab
First command for Stale release is still live	readlink -f /srv/www/example.com/current	topicladder vps debugging lab
Expected output for Stale release is still live	The current symlink, page body, or asset version does not match the release you expected.	topicladder vps debugging lab
Fix checklist for Stale release is still live	Flip the current symlink to the intended release.; Use a cache-busting URL to verify.; Record the live release path in the project note.	topicladder vps debugging lab
Second verification command for Stale release is still live	curl -sS https://example.com/ | grep -n 'expected text'	topicladder vps debugging lab
What not to do for Stale release is still live	Do not jump to broad edits before the inspection command proves the failing layer.	topicladder vps debugging lab
Clue: The site worked before, but the browser now warns about an expired or invalid certificate.	Likely diagnosis: Renewal cannot prove domain control or cannot run its configured renewal path.	topicladder vps debugging lab
First command for Certificate renewal failed	certbot certificates	topicladder vps debugging lab
Expected output for Certificate renewal failed	The certificate list, dry run, or logs name the failing domain, challenge route, or renewal hook.	topicladder vps debugging lab
Fix checklist for Certificate renewal failed	Fix the named DNS or HTTP challenge issue.; Confirm port 80 reaches the right host.; Run a dry run before relying on automatic renewal.	topicladder vps debugging lab
Second verification command for Certificate renewal failed	sudo certbot renew --dry-run	topicladder vps debugging lab
What not to do for Certificate renewal failed	Do not jump to broad edits before the inspection command proves the failing layer.	topicladder vps debugging lab