WordPress crashes happen very rarely but when they do, they can cause a great deal of stress. Fortunately, they are most often very easily fixed without any loss of content.It has been my experience that 99% of the time any issues with WordPress is plugin related. A site may work fine for a while, then an update in either the WordPress program or a plugin will cause an incompatibility issue causing the database to fail. Troubleshooting a WordPress crash is very easy and you can be back up and running in a few minutes. The first, and most obvious place to start is to look at any recent changes you may have made, an update or a new plugin installation. Sometimes though, it is not so obvious.
Steps to troubleshooting a WordPress crash:
Since you most likely will not be able to access the dashboard of your WordPress installation, you must have access to your files either through an FTP client or from the File Manager in your web hosting cPanel. Navigate to the wp-content folder in your file manager or ftp.
Open that folder and inside you will see a plugins folder.
Rename the plugins folder plugins.bak
Create a new folder (directory) and call it plugins.
Check your website. If the website now loads, you have verified that it is indeed a plugin compatibility issue.
If you are running an older version of WordPress, now is a good time to upgrade to the latest, most stable version.
Once the latest version is installed, you can begin to troubleshoot to find out which of your plugins is causing the incompatibility issue.
Reinstall your plugins one at a time. After each installation, test your site to make sure it is still working properly. Update each plugin to the newest version if there has been an upgrade made available.
If at any time during this process your WordPress crashes again, you know you have found the culprit. Simply access your cPanel or FTP again and delete the plugin.
You will need to either download a newer version of that plugin directly from the developer source or wait for an update to become available for it before you can install that plugin again.
Most plugin developers work tirelessly to keep their plugins up-to-date with the latest versions of WordPress, but occasionally an update is a little slow in coming or the WordPress update is a major one that has changed the core functions of the program and the developers have not been able to keep up.
Steps to take when the WordPress crash is not plugin related:
If you have tried the above and the troubleshooting has not been a plugin issue, there are two other areas you can try.
Go into your cPanel and into the MySQL panel that will bring up the list of databases installed on your account. Click on the restore/repair database. If the crash was due to damage to your database, this should correct the problem.
You should have a database backup on file. (install a plugin to take care of this on a regular basis if you haven't already) You can do a database restore from your backup file. If you have not been in the habit of backing up your sites, and you do not have any backup files, I am sorry to say that you may have lost your website. You will need to contact support to see if they have any recent backups or if they can offer any support.