Gateway error after publishing reports

Hi All, 

Since a week I have an issue with publishing reports to our PBI workspaces. Publishing the reports works fine, but when I open the report on PBI Service I get this error: "No gateway selected to acces the data source ...".  I don't understand why it's asking for a gateway. In the past I published many reports to the workspaces and they all work fine without setting up a gateway. 

To make it better, I asked my colleague to publish the report for me and when he published it, the report worked as it should. 

A week ago this issue started. I believed it was caused by a report where I make of use of 2 Excel files which are on OneDrive/Sharepoint, but now I also have this problem when I publish reports with only our data warehouse as a data source. So I seriously doubt that the excel files are the issue. 

Does anyone recognize this issue and know how to solve it?

To be clear, I prefer to publish without a gateway. 

Any help is really appreciated.