You have to use a username and password. You need to be authorized to view the information on the phone, which only the phone's owner, or another authorized user is allowed to do.
Otherwise, it would be a security hole, where any user could view the current display of any other users phone just by knowing the phone's IP address. Some organizations might not mind, but others would.
Try creating a user, and associating that user with your phone. Enter that username and password in the dialog, and it should work...
Unfortunately, the super provider doesn't work here, as it's meant for jtapi, and not this (to my knowledge, at least - I've tried using the superprovider account for this app and it didn't work...)
So you'll have to associate every phone you would like to access with this application with your user. You can use the same user for all of the phones, you don't need a separate user for each phone, at least! But you'll have to remember to add new phones to your user account...
