Currently, the WP File Manager plugin on version 7.2.2 or greater does not work here at Pressable. Use the Advanced File Manager instead and setup following the guide below.
The Advanced File Manager plugin allows you to view, edit, delete, and upload files from the WordPress dashboard interface on your website.
On Pressable, the Public Root Path will need to be adjusted for the plugin to function properly and show the correct site installation.
This can be done by activating the plugin and then navigating to File Manager > Settings and look for the Public Root Path.

You will need to change the Public Root Path to:
/srv/htdocs
Then click Save Changes and reload the Advanced File Manager and you’ll see the site files displayed properly.