Changed a site name in BT Panel, the database was written, the panel restarted — and the UI still showed the old name. There were three different db files with a sites table, and the one actually in use was hidden at data/db/site.db.
Origin certificate installed, yet Cloudflare still reported 526 Invalid SSL Certificate. After a long detour, the cause was the SSL mode set to "Automatic" — it is not a fixed mode but a dynamic decision, and an incomplete chain gets rejected outright.
Debugging an HTTPS failure: the firewall allowed it, the port was open, yet Cloudflare kept returning 521. The root cause was that Nginx was never listening on 443 — a closed port behaves completely differently from a firewall drop.
