Error on Refresh - no change in circumstances!

[MPDataAnalytics]

I have had no change in circumstances to the way i am saving data, or generating my reports and i am getting the below:

{"error":{"code":"Premium_ASWL_Error","pbi.error":{"code":"Premium_ASWL_Error","parameters":{},"details":[{"code":"Premium_ASWL_Error_Details_Label","detail":{"type":1,"value":"We are unable to refresh the semantic model because the model uses a data connection configured for Workspace Identity authentication, but the workspace has no identity, or the model owner does not have permissions to use the workspace identity. Please configure a workspace identity and make sure the model owner has Contributor (or higher) access to the workspace, or use a different authentication method."}}],"exceptionCulprit":1}}

Can anyone offer any advice whatsoever!