All servers automatically restart within 5 seconds if they fully crash (stop executing). Crashes are uncommon for most servers but can occur in a variety of circumstances, such as if the game or one of the installed plugins has a bug; if files were forgotten when uploading a custom configuration; or if an invalid map is specified.
Our system monitors servers remotely at 5-minute intervals. If a server freezes (stops responding), it will notice this within 5-10 minutes and remotely restart it. If the server still isn't responding after another 5 minutes, the system will run a generic repair script that attempts to check for common configuration mistakes.
If your server begins to frequently crash, contact us and we can work with you to determine the cause.