Data source credentials greyed out

All,

I am trying to deploy my tabular model from Visual Studio to the Power BI Premium workspace.

I follow the instructions as documented here:

https://docs.microsoft.com/en-us/power-bi/admin/service-premium-connect-tools#deploy-model-projects-from-visual-studio-ssdt

Unfortunately I cannot select Data source credentials as is specified in the procedure, because it is greyed out. Please refer to the screenshot below.

Any tips on how to activate this tab, or how to get the data transfer to succesfully deploy my tabular model?

Thanks