Our Website is down still but EC2 Instance says running

When your EC2 instance shows as "running" but your website is still inaccessible, there are several potential causes to investigate:

1. Web Server Status: Even though your EC2 instance is running, the web server software (like Apache, Nginx) might have stopped. You'll need to SSH into your instance and check if the web server service is running properly, then restart it if necessary.

2. Security Group Configuration: Verify that your EC2 instance's security group still allows incoming traffic on ports 80 (HTTP) and 443 (HTTPS) from all sources (0.0.0.0/0). Security group rules might have been changed during the outage.

3. Network Configuration: Ensure that your subnet's route table includes a route for internet-bound traffic pointing to the internet gateway.

4. DNS Configuration: Check that your domain's DNS settings are still correctly pointing to your EC2 instance's public IP address.

5. Application Issues: The outage might have caused your application to crash or enter an error state while the underlying EC2 instance continues running.

To troubleshoot:

• SSH into your instance and check your web server logs for any error messages
• Verify the web server is running with the appropriate service status command
• Try accessing the site using the EC2 instance's public IP directly to rule out DNS issues
• Check for high resource utilization (CPU, memory) that might be affecting performance
• Restart your web server service, and if that doesn't work, consider restarting the EC2 instance

If you recently made any changes to your infrastructure or if the outage caused configuration changes, you might need to review and restore proper settings.
Sources
My website on EC2 reports it is running but no one can see it | AWS re:Post
Suddenly "This site can’t be reached" | AWS re:Post
EC2 Website Connection Timeout | AWS re:Post