Your user sees this error they haven't been set up in Synergy, or haven't got permissions for the module they're trying to use.
To check the user's group and permissions, follow these steps.
Open Security Manager, then click the users toolbar icon.
In the Search field, check to see if the user exists and that their username has been correctly entered.
If they don't exist, click Add New User and populate all mandatory fields highlighted with a red border.
Add security groups to the user by clicking Add Security Group, then selecting the appropriate groups.
Save by pressing Ctrl + S or clicking the save icon.