Z.com for WordPress use a specialized system for WordPress, that is safe and secured.
However, it has often been attacked by hackers due to its open source nature.
So please make sure the following notice is fully understood and practiced.
・Make sure that the themes and plug-ins you use are the official and support the latest version of WordPress
・Test the plugin to make sure that it works, and then confirm it is the latest version
・Use a strong password
・Use a file transfer service that is safe and secured
・Encrypt the data and transfer it over
・Always create a backup copy