In order to allow a user to sync Dimensions with aCloud/Access Evo, the user must have the option enabled in their user record. To do this:
Log into Dimensions
Click System, User Records
Select the relevant user in the list.
At the top, click Options.
Click the Edit, pencil and paper icon.
Select the Workspace User check box.
Click Save. The user may need to log out and back into Dimensions for the changes to take effect.