The password has probably changed just fine. Please verify that you cannot log in with the new password. After reloading a user in the User manager, the password field is always set to 8 ‘*’s
The reason is simple. Passwords are not actually stored by Cerberus FTP Server. Instead, a secure hash (SHA1, if you are curious) is generated and stored. It is impossible to reverse engineer the password from the secure hash, thus it is impossible to know the length of the password.
This is the standard technique most applications use to store password information. Any other method is usually considered insecure and should be employed only when absolutely necessary.
I am having the same issue, I noticed what you had mentioned, but when I test the FTP I am having a password issue. I have uninstalled and reinstalled the app and upon creating a new user and password, I am never able to log on.