Verify the FTP user, used to log into NGASI AppServer Manager has shell or login access
enabled (this is set in the Domain setup or "Web Hosting Settings" in Plesk).
In cPanel, the Domain FTP user is setup either when the account is created
or when setting up the Domain.
Also check with your Administrator that the user was assigned access to
NGASI AppServer Manager
NOTE: If you reset the System or FTP user associated with the Application server,
the Operating System and/or Control Panel may delete all the files in the directory.
In that case you would need to re-install the Application Server via
NGASI AppServer Manager.