They are several version of the Protel property management system. We have put together a guide to checking which version you have and whether it is Protel On-Premise or Protel Air (which we do not support).
To look up the installed release version of Protel, open then help menu in the Protel menu bar and then click on About Protel. You will find the release information at the top of the dialog:
Properties using Protel Air will be connecting through a browser and going to the URL https://connect.protel.net to connect, below is an example of the login window:
Once you have logged in, you will see the following page:
As you can see the above clearly shows Protel Cloud Center, which only appears in Protel Air.