Refresh not possible after Join in Query

Hello all,

i did a simple Table.NestedJoin of two tables in the Power Query and a Table.ExpandTableColumn (extended the table with two columns after join). 

Result is that in Power BI Service the refresh no longer works. I get following error message:

• Fehler bei der Datenquelle{"error":{"code":"DM_GWPipeline_Gateway_MashupDataAccessError","pbi.error":{"code":"DM_GWPipeline_Gateway_MashupDataAccessError","parameters":{},"details":[{"code":"DM_ErrorDetailNameCode_UnderlyingErrorCode","detail":{"type":1,"value":"-2147467259"}},{"code":"DM_ErrorDetailNameCode_UnderlyingErrorMessage","detail":{"type":1,"value":"Informationen werden benötigt, um Daten zu kombinieren. Geben Sie eine Datenschutzebene für jede Datenquelle an."}},{"code":"DM_ErrorDetailNameCode_UnderlyingHResult","detail":{"type":1,"value":"-2147467259"}},{"code":"Microsoft.Data.Mashup.MashupSecurityException.DataSources","detail":{"type":1,"value":"[{\"kind\":\"SQL\",\"path\":\"SQL;DWH\"},{\"kind\":\"SQL\",\"path\":\"sql;dwh\"}]"}},{"code":"Microsoft.Data.Mashup.MashupSecurityException.Reason","detail":{"type":1,"value":"PrivacySetting"}}],"exceptionCulprit":1}}} Table: NEW_JOINED_TABLE.

I checked all in Service (Settings) and in Desktop (Data source settings) but nothings works until now. Someone more ideas?

Best regards