Project Web App could not complete the command you requested from Project Professional because you currently have an active ...

{Project Web App could not complete the command you requested from Project Professional because you currently have an active delegate session in Project Web App.}While you are in a delegate session, Project Professional will be offline and disconnected from the server. After you stop the delegate session, you can reconnect to the server by clicking the File tab, clicking Info and clicking the Connect to Server button.