High severitygateway
Power BI Refresh Error:
DM_GWPipeline_Gateway_MashupDataAccessError
What does this error mean?
The on-premises data gateway failed to access the data source during the Mashup (Power Query) evaluation phase. This is one of the most common gateway errors in Power BI.
Common causes
- 1Data source credentials stored in the gateway are expired or incorrect
- 2The gateway service account lacks read permissions on the data source
- 3Network connectivity between the gateway machine and the data source is blocked
- 4The data source server is unreachable or temporarily down
- 5Firewall or proxy rules blocking outbound connections from the gateway host
How to fix it
- 1Open Power BI Service → Settings → Manage gateways and verify credentials for the affected data source
- 2Re-enter the credentials for the data source even if they appear valid — this forces a re-validation
- 3Log into the gateway machine and manually test connectivity to the source (ping, telnet, or SSMS)
- 4Check Windows Event Viewer on the gateway host for additional error detail (Application log, source: On-premises data gateway)
- 5Ensure the gateway service account (not your personal account) has the necessary database permissions
- 6If using a firewall or proxy, confirm the gateway machine can reach the source host on the correct port