The administrator password, assuming it has been set using the guest customisation system, can be retrieved by accessing your server by either selecting vApps, the desired vApp, then click the label of the virtual server, or select Virtual Servers and click the label of the desired virtual server.
From the overview, click the 'password' link to retrieve the password that was set by guest customisation. The word 'password' will be replaced by the password set by guest customisation.
Note that this only stores the password set by guest customisation - if the password has been changed through the guest operating system, this will not be reflected in the Cloud IaaS interface.
Should you need to reset your administrator password, for example it's been recently changed and you can no longer login, you can do this through Guest Customisation. For details on how to apply these changes, please see https://support.neural.com.au/hc/en-us/articles/360000204516-Updating-Guest-Customisation