Basic:
- Does your DNS A record point to the correct IP address?
- Does DNS checker show mostly green marks for your domain and does it show the expected IP address?
- Does ping <server IP address> get a response?
- Has at least 4 hours passed since you updated the A record?
- Does ping <domain name> show the expected IP address and get a response?
- Is your web server running?
- Is the web app called by your web server running?
Extra:
- Check if the correct ports are open and listening.
- Ensure no firewall rules are blocking access to the web server or specific ports.
- Review web server logs (e.g., Apache, Nginx) for any unusual entries.
- Verify that SSL certificates are valid and have not expired.