This either means that the username and password information in your
settings.php file is incorrect or we can't contact the MySQL database server. This could mean your hosting provider's database server is down.
The MySQL error was: mysqlnd cannot connect to MySQL 4.1+ using the old insecure authentication. Please use an administration tool to reset your password with the command SET PASSWORD = PASSWORD('your_existing_password'). This will store a new, and more secure, hash value in mysql.user. If this user is used in other scripts executed by PHP 5.2 or earlier you might need to remove the old-passwords flag from your my.cnf file.
Currently, the username is katyclark and the database server is localhost.
For more help, see the Installation and upgrading handbook. If you are unsure what these terms mean you should probably contact your hosting provider.