Caddy ACME/DNS Troubleshooting

Error	Meaning	Fix
no valid A records	DNS not pointed to VPS	Add A records for root/subdomains
bind: address already in use	nginx still bound to :80	sudo systemctl disable --now nginx
unrecognized directive: rate_limit	Not in Caddy core	Remove or use proper plugin
permission denied /etc/caddy	Wrong ownership	sudo chown -R caddy:caddy /etc/caddy

Command helpers:

sudo caddy validate --config /etc/caddy/Caddyfile
sudo systemctl restart caddy
journalctl -u caddy -f