A message “This content is being edited by other user.” appears, and authoring cannot be performed.

Appears when the relevant content is locked.
The content will be locked when it is currently being edited or when the screen is closed before the completion of the editing.
The relevant content can be manually unlocked when another user is not editing it.Check the status of the relevant content on the Contents List screen of the CMS.
Clicking the “Unlock” button displayed on the screen will unlock the content.