You'll need to login.  If you are logging in, you also need permissions:

This method might require any of the following privileges depending on where the property fits in the inventory tree.

• System.View on the root folder, if this is used to read settings in the "client" subtree.
• System.Read on the root folder, if this is used to read all settings or any settings beside those in the "client" subtree.
• System.Read on the host, if this is used to read the advanced options for a host configuration.