Scheduling Refresh with two Data Sources

Hello, 

currently I have a Gateway Connection to a PostgreSQL Server and I have schedules Imports, which work well. However when I try to add another data source to the data model in Power BI Desktop such as a CSV file, then the scheduled import breaks on the Service side. 

What I want at the end is to keep the Scheduled Imports as previously but just have this additional source of information (A CSV file), which I would manually update from time to time (no need for scheduled refresh there).

I know that this topic has been asked here before but it was more about Azure and I guess this would be a slightly different topic.

I appreciate your help!