can't get scheduled refresh working (table schema unexpected error)

Hi to all,

After googling for results for couple of days and reading all the online tutorials and guides, I couldn't solve my problem and decided to post here.

I've installed Power BI Reports Server and created a report. The report gets data directly from SQL server via import (not direct query).

The report works fine local also I can publish it on report server.

I put priviledged account details into "Data Sources", test the connection and it connects successfully. However, wher I configure scheduled refresh, it can't refresh data. The error is "Data refresh failed. Please try again later or contact your administrator."

"SessionID: a078eba9-3b8a-460c-8cd2-e8cf6d9f73bd [0] 0: Connection string discovery: table schema unexpected."

Also the log file output is below:

2021-08-20 00:00:07.3863|INFO|11|Handling event with data: TimeEntered: 19.08.2021 21:00:00, Type: Event, SessionId: 0bc961b2-bd55-4536-9198-aec5750f7d0e, EventType: DataModelRefresh
2021-08-20 00:00:07.4123|INFO|11|Processing Data Model Refresh: SessionId: 0bc961b2-bd55-4536-9198-aec5750f7d0e, Status: Starting Data Refresh.
2021-08-20 00:00:07.4123|INFO|11|Processing Data Model Refresh: SessionId: 0bc961b2-bd55-4536-9198-aec5750f7d0e, Status: Starting Retrieving PBIX AsDatabaseInfo.
2021-08-20 00:00:07.4643|INFO|44|Finding model for refresh with catalogId=21e08903-82be-4c58-a1ad-f7a340b6f8df, lastCatalogItemUpdate =19.08.2021 09:46:10, lastModelUpdateinCatalog=19.08.2021 09:46:16, resolved to database name=21e08903-82be-4c58-a1ad-f7a340b6f8df_949828950, wasInMemory=True
2021-08-20 00:00:07.4713|INFO|11|Processing Data Model Refresh: SessionId: 0bc961b2-bd55-4536-9198-aec5750f7d0e, Status: Starting Verifying all the data sources are embedded.
2021-08-20 00:00:07.4952|INFO|11|Processing Data Model Refresh: SessionId: 0bc961b2-bd55-4536-9198-aec5750f7d0e, Status: Starting Verifying connection strings are valid.
2021-08-20 00:00:07.5072|INFO|11|Processing Data Model Refresh: SessionId: 0bc961b2-bd55-4536-9198-aec5750f7d0e, Status: Starting Streaming model to Analysis Server.
2021-08-20 00:00:07.6132|INFO|15|LoadDatabaseAsync: Successfully EnsureDbLoaded clientSessionId=0bc961b2-bd55-4536-9198-aec5750f7d0e, databaseName=21e08903-82be-4c58-a1ad-f7a340b6f8df_949828950, modelId=1413506852, alreadyLoaded=True
2021-08-20 00:00:08.2188|INFO|11|Processing Data Model Refresh: SessionId: 0bc961b2-bd55-4536-9198-aec5750f7d0e, Status: Starting Refreshing the model.
2021-08-20 00:00:08.6142|INFO|11|GetDataSourcesCollection: databaseName=21e08903-82be-4c58-a1ad-f7a340b6f8df_949828950, PowerBIDataSourceVersion=PowerBI_V3
2021-08-20 00:00:08.6454|ERROR|11|Error Processing Data Model Refresh: SessionId: 0bc961b2-bd55-4536-9198-aec5750f7d0e, Status: Error Failed to refresh the model, Exception [0]Microsoft.AnalysisServices.Azure.Common.DataSourceDiscoveryException: Connection string discovery: table schema unexpected.
TemplateMessage: Data source discovery failed on database .

Any help will be greatly appreciated.

Sertan