How can I achieve schedule refresh?

I have a Power BI Desktop dashboard that has 4 data connections. 3 of them are in my laptop (xlsx) and one is connected to a oracle database with import mode. I have 2 calculated columns in the table from the oracle database. This dashboard is published in power bi service with a pro license. 

I want to schedule refresh every morning, so the dashboard is always updated. When I try to manually refresh from power bi in the web, i get this error: 

If I try to schedule refresh, the "Data Source Credentials" button is disabled. 

I checked the data source credentials in Power Bi Desktop and they're ok.

I don't know i'm missing something but anyone here knows how can I achieve this? Is it possible with import query? What am I missing? 

Thanks for your help!