DNS setup

Create an A record for the hostname that points to the VPS IPv4 address. Add an AAAA record only when IPv6 is configured and reachable. DNS changes can take time because recursive resolvers cache earlier values.

Before requesting a certificate

Confirm that the domain resolves to this VPS and that the intended web service responds on ports 80 and 443. Remove conflicting proxy or firewall rules before retrying certificate issuance.

Security

Use HTTPS for sign-in pages and application APIs. Redirect plain HTTP after certificate issuance succeeds. Keep certificates and account recovery information in your backup plan. Never expose database, container-management, or internal application ports directly unless the application documentation explicitly requires it.