Error establishing a database connection

When encountering an "Error establishing a database connection" error on a WordPress site hosted on AWS Lightsail, there are several steps you can take to troubleshoot and resolve the issue:

1. Check the database credentials: Verify that the database name, username, password, and host information in your wp-config.php file are correct. These should match the credentials provided in the Bitnami console for your Lightsail instance.

2. Restart the database service: The MySQL or MariaDB service may have stopped running. Try restarting it using the Bitnami control script:

sudo /opt/bitnami/ctlscript.sh restart mysql

3. Check database service status: Verify if the database service is running:

sudo /opt/bitnami/ctlscript.sh status

4. Review error logs: Check the WordPress error logs and database error logs for any specific error messages that could provide more insight into the issue.

5. Ensure sufficient resources: Make sure your Lightsail instance has enough resources (CPU, RAM, storage) to handle the current load. You may need to upgrade your plan if you're experiencing resource constraints.

6. Check for recent changes: If the error occurred after updating plugins, themes, or WordPress core, try reverting those changes to see if it resolves the issue.

7. Verify file permissions: Ensure that the WordPress files and directories have the correct permissions set.

If these steps don't resolve the issue, you may need to restore from a recent backup or seek further assistance from AWS support or the WordPress community forums.
Sources
Error establishing a database connection - Lightsail and Wordpress | AWS re:Post
Error establishing a database connection - Lightsail & Wordpress | AWS re:Post
can't update or upload file in filezilla & error establishing database connection | AWS re:Post

Hello,

Please provide additional information when you are able to do so.

1. Have you recently changed the configuration of your WordPress application either by manually editing configuration or PHP files, or have you recently installed plugins? There may be syntax errors in recently modified files causing the error.
2. Running the bitnami scripts to check on the status of your application can provide helpful information. If any of it is stopped, using the /opt/bitnami/ctlscript.sh to restart them can help.

You may also find the bitnami WordPress documentation helpful: https://docs.bitnami.com/virtual-machine/apps/wordpress/troubleshooting/debug-errors/ https://docs.bitnami.com/aws/apps/wordpress/troubleshooting/debug-errors-apache/