There is not possible to enable SFTP in Plesk in
Control panel > Webhosting Plesk > Service nodes > Tools and settings as it is described in Plesk article.
Security policy option is not visible.
Some Plesk configuration options are hidden due to security reasons.
This behavior is refactored in Odin Automation 8.2 and Plesk 17.8. Upgrade according to "Upgrading the Webhosting Plesk Module (OA 8.2)" article.
As a workaround, it is possible to login to Plesk panel directly under
Root user (avoiding redirect from Odin Automation control panel.