Error on Mariadb & Apache

It seems you are dealing with a multi-layered issue affecting your WordPress site's functionality. Here's my take at a structured approach to diagnosing and potentially resolving the problem:

1. Cloudflare Error 521:

   • This error indicates that Cloudflare is unable to establish a connection with your server.
   • Since pausing Cloudflare didn't resolve the issue, it's possible that the problem lies with your server settings or resource allocation.

2. Server Resource Issues:

   • Low RAM could be causing the server to fail to respond to Cloudflare's requests.
   • Consider scaling your AWS Lightsail instance to provide more resources.

3. Apache and MariaDB Errors:

   • The timeout errors from Apache suggest that PHP-FPM is taking too long to respond. This could be due to resource constraints or configuration issues.
   • The errors related to wp-config.php and undefined array key "HTTP_HOST" indicate a potential misconfiguration in your WordPress settings.
   • The standard error message from MariaDB regarding std::error_code::default_error_condition() is rather vague, but it might be connected to the low RAM issue as well.

4. Connectivity:

   • If ports 22, 80, and 443 are not publicly accessible, this could also be part of the issue. Make sure your AWS security groups and network ACLs allow traffic on these ports.

5. Troubleshooting Steps:

   • Resolve Resource Issues: Upgrade your server or allocate more resources to handle the load.
   • Fix Apache Configuration:
     • Increase the PHP-FPM timeout settings.
     • Check for any .htaccess misconfigurations.
   • Resolve PHP Warnings:
     • Address the HTTP_HOST warnings in wp-config.php by ensuring that the $_SERVER['HTTP_HOST'] variable is defined or by providing a fallback value.
   • MariaDB:
     • Investigate the MariaDB error further by checking the MariaDB error log for more details.
   • Networking:
     • Ensure that the AWS security groups and network ACLs are configured to allow traffic on the necessary ports.
   • Cloudflare Settings:
     • Revisit Cloudflare settings to ensure that SSL/TLS encryption mode is correctly set to “Full” if you have a valid SSL certificate on your server, or to “Flexible” if you don't.
     • Make sure that the Cloudflare IP ranges are whitelisted on your server's firewall.

6. Monitoring:

   • Once the above steps are taken, monitor the server logs to see if the errors persist.
   • Utilize Cloudflare's analytics to check for any network-related issues.

Given the complexity and critical nature of the issue, if these steps do not resolve the problem, and you still have a support case open, request further escalation with the Lightsail team if that option is available to you. Additionally, it's important to ensure that you have backups of your website before making significant changes.

Hi,

You can follow this doc to check your Lightsail instance firewall settings and see if it comply with Cloudflare requirements https://lightsail.aws.amazon.com/ls/docs/en_us/articles/understanding-firewall-and-port-mappings-in-amazon-lightsail

If RAM is the constraint, you can also consider migrate to a larger instance, you can follow this doc to launch a new instance from snapshot https://lightsail.aws.amazon.com/ls/docs/en_us/articles/how-to-create-larger-instance-from-snapshot-using-console

in the end the problem proved to be too challenging, even with your help... I followed several steps but nothing. I took another older instance and worked on that, eliminating the one with the error. Thanks anyway for your assistance