When encountering a “could not connect to MySQL” error, it’s imperative to methodically check the database settings in your configuration file. Start with verifying the host, username, password, and database name parameters. Ensure that the host is correctly set to the proper database server’s IP address or hostname (e.g., ‘localhost’ for a local server or an external IP for remote access). Additionally, confirm that the username and password are accurate and have appropriate permissions for the specified database. If you’re using a configuration management tool or deployment script, check that these credentials are being correctly passed to your application.

Next, examine if the MySQL service is running on the server. You can do this by executing a command such as `systemctl status mysql` on systems using systemd, or `service mysql status` on older systems. If the service is down, initiate it with `systemctl start mysql` or the equivalent command, depending on your server’s operating system. Also, investigate the MySQL error logs for any reported issues during startup or connection attempts. If you’re using a firewall or security group settings, ensure that the port (default 3306 for MySQL) is open for incoming connections. Finally, consider whether your application and the MySQL database are compatible in terms of software versions and configurations.