Error: 521 Not logged in - Secure authentication required

By default, Cerberus will configure FTP listeners to not allow unencrypted FTP connections.

A user will receive a “521 Not logged in – Secure authentication required” if they attempt to login using unencrypted FTP when secure connections are required.

If you wish to allow unencrypted FTP, you have to change the FTP listener to allow it. Here are the steps:

1. Open the Server Manager and select the Listeners page.
2. Select the IP address of the FTP listener you are trying to log in on.
   Do not select the Default FTP listener. Changes to the Default listener will only be applied to any new IP addresses that are detected later.
3. Un-check the options for Require Secure Control and Require Secure Data.        
4. Press Update to close the Server Manager and save your changes.

Note: Allowing unencrypted FTP is HIGHLY discouraged. Your transmissions are not encrypted and your data can easily be modified in transit without you knowing.