Unable to connect to the database
From Joomla! Documentation
Unable to Connect to the Database: Could Not Connect to MySQL
If during or after installation, you received an "Unable to connect to the database" error, verify that you have entered your MySQL/MariaDB database details correctly. The installation script will not allow you to continue unless the details are correct. Note that you are not expected to create a password for the database during installation - the error may then be due to entering a password which doesn't exist:.
If the failure occurs after moving your site to another host, check the following items of your configuration.php file. The normal database settings are the following:
var $dbtype = 'mysql'; var $host = 'localhost'; var $user = 'user_with_database_access'; var $db = 'the_actual_database_name'; var $dbprefix = 'table_prefix_';
The Most Common Reasons
- Sometimes you will see this message if MySQL/MariaDB has stopped running on your server. Your server administrator may temporarily shut down MySQL/MariaDB to perform maintenance. In such circumstances, your site will likely return shortly.
- Your database user has been deleted. If this is the case, you will need to recreate your database user with the same username and password that existed when you first installed Joomla. Use your domain control panel to administer this or contact your server administrator.
- Your database username or password has changed.