I found this error when try to add new datasource setting below on premise gateway. I'm trying to connect to SAP BW (DirectQuery). I have changed regional language in the gateway to English (United Kingdom). I have installed SAP .Net connector in gateway. But the error still persist. Kindly need your advice.
Do you connect it via SAP BW connector in Power BI Desktop or custom connector?
If you connect it via SAP BW connector in Power BI Desktop and then publish to Service, add data source under on premises gateway as this article.
Please compare the default logon language against the list of imported languages in tcode SMLT, you would need to change the default logon language or import the language into SAP BW if it doesn’t exist.