The DM_GWPipeline prefix in Power BI error codes identifies errors that originate in the on-premises data gateway pipeline — the infrastructure that routes requests from Power BI Service through the gateway to the on-premises data source. Understanding the sub-error after the prefix tells you where in the pipeline the failure occurred.
Common DM_GWPipeline sub-errors
DM_GWPipeline.Client.GatewayUnreachable: The gateway machine cannot be reached from Power BI Service. The gateway service may be stopped, the machine may be offline, or a network/firewall change may be blocking connectivity. Check the gateway's Windows service status and network connectivity first.
DM_GWPipeline.Gateway.MashupDataAccessError: The gateway successfully connected to Power BI Service but failed to access the data source when executing the Power Query mashup. This is usually a credential problem, a network issue between the gateway machine and the data source, or a data source that's temporarily unavailable.
DM_GWPipeline.Gateway.ServiceBusConnectionFailed: The gateway cannot connect to Azure Service Bus, which is used for communication between Power BI Service and the gateway. This is typically caused by outbound port 443 or 5671 being blocked by a firewall or proxy on the gateway network.
DM_GWPipeline.Gateway.QueryCancelled: The query was cancelled — either because it exceeded the query timeout, because the user cancelled it, or because the gateway queue was cleared. Check query duration and the gateway's queue load.
DM_GWPipeline.Gateway.DatabaseError: The gateway reached the data source but the database itself returned an error. This is often a SQL Server-level error (permission denied, database offline, query execution failed) rather than a gateway issue.
DM_GWPipeline.Gateway.CertificateNotTrusted: The SSL/TLS certificate presented by the data source is not trusted by the gateway machine. This can happen after certificate renewal if the new certificate chain is not properly installed.
Diagnosing DM_GWPipeline errors systematically
For any DM_GWPipeline error:
- Check if multiple datasets failed at the same time — a multi-dataset failure suggests a gateway-level issue rather than a data-source-level issue
- Check the Windows Event Viewer on the gateway machine (Application log, source: On-premises data gateway) for additional detail
- Verify the specific data source is accessible from the gateway machine by testing the connection directly
- Check the gateway's network connectivity to Azure Service Bus if multiple error types are appearing