404 for TinyMCE button

This appears in Chrome Inspector’s Console when clicking the Filebase TinyMCE button:

GET http://domain.com/wp-content/plugins/wp-filebase/editor_plugin.php?post_id=14106&content=%3Cp%3E%A0%3C/p%3E%3Cp%3E%A0%3C/p%3E 404 (Not Found)

https://ww.wp.xz.cn/plugins/wp-filebase/