I keep having and error saying "Unable to connect to the data source undefined. Please try again later or contact support. If you contact support, please provide these details." even though I have everything right in the gateways.
When I update this in power BI desktop, it works fine but once I publish and refresh, the same error keeps appearing.
Have you configured the gateway correctly for all relevant data sources? In addition, since the error "data source undefined" is quite broad, it is difficult to pinpoint the details of the error, so some more detailed information is needed. So would you mind sending me a screenshot of the full error message?