Sometimes your WordPress website may be not responding or load with a blank page. This is most likely results from a corrupted plugin or theme. It may be caused due to other issues also.
If you are using older version of WordPress like 3.1.x, then incorrect information in your wp-config.php file can cause a white page to appear. If the MySQL username or MySQL password in this file are incorrect may also cause a white page.
To fix this issue you must create a new MySQL user and update the wp-config.php file to have the new MySQL username and MySQL Password. You can simply locate the following information and update the username and password.
/** MySQL database username */
define ('DB_USER', 'user_wp');
/** MySQL database password */
define ('DB_PASSWORD', 'password');
You can easily determine if it is a plugin causing the issue by disabling the plugins temporarily. When a plugin is the issue, it is unlikely you will be able to access to the WordPress Admin Dashboard to disable the plugin.
You can determine if it is a plugin issue by simply renaming the directory that stores the plugins. This will disable all of your plugins, but it will allow you to access your WordPress. To disable a specific plugin, you can look under the /wp-content/plugins/ directory of your WordPress installation. If your WordPress loads after renaming it, it is likely that specific plugin that is causing the issue.
If it is not a plugin issue, then it may be a theme related issue. If you can access to the WordPress Admin Dashboard, we recommended you to simply log in and change to default theme. Though there may be some issues which can cause you to lose access the WordPress Admin Dashboard.
To change the theme, you need to access the database directly using phpMyAdmin.
To determine the database configured for the WordPress, you need to look inside the wp-config.php file to the line: define ('DB_NAME', 'user_wp');
Then go to phpMyAdmin and select the wp_options table from the list. Inside of this table you will see a list of rows. Go to the option_name template and stylesheet to change the theme. You can change the theme under option_value.