Refresh in Power BI service gives errors

Thanks for GilbertQ's concern about this issue.

Hi, haraldinti 

I am glad to help you.

DM_GWPipeline_Gateway_MashupDataAccessError usually indicates that there is a problem with the data gateway or data source connection in the Power BI service.

You can try restarting the data gateway. Sometimes, simply restarting the on-premise data gateway can resolve connection issues.

And you should make sure that the account running the Power BI On-premise Data Gateway has the necessary permissions to access the data source.

Since the error mentions conversion issues with the value “[Table]”, double check your query transformations in Power BI Desktop to ensure there are no implicit type conversions that might cause issues when published to the service

If the issue persists, consider uninstalling and reinstalling the On-premise Data Gateway.

I hope my suggestions give you good ideas, if you have any more questions, please clarify in a follow-up reply.
Best Regards,
Fen Ling,
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