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High severitydata source

Power BI Refresh Error:
SqlFailedToConnect

What does this error mean?

ADF or Fabric could not connect to SQL Server or Synapse. The server is unreachable from the integration runtime — check firewall rules and DNS.

Common causes

  • 1The SQL server name or endpoint URL in the linked service is incorrect
  • 2Firewall rules on the SQL server or Azure SQL/Synapse do not allow the integration runtime's IP
  • 3The SQL Server is not accessible from the self-hosted integration runtime network
  • 4The SQL Server is offline, restarting, or under maintenance
  • 5For Azure SQL/Synapse: the 'Allow Azure services' firewall rule is disabled and the IR IP is not listed

How to fix it

  1. 1Verify the server name in the linked service — for Azure SQL: <server>.database.windows.net.
  2. 2Add the integration runtime's public IP to the SQL Server firewall under Networking → Firewall rules.
  3. 3For Azure SQL/Synapse: enable 'Allow Azure services and resources to access this server' if using Azure IR.

Beyond the docs

Common practitioner solutions not covered in the official documentation.

  1. 1Test TCP connectivity from the self-hosted IR machine: Test-NetConnection <server> -Port 1433
  2. 2Check SQL Server is running and accepting connections via SSMS from the IR machine
  3. 3For private endpoints: verify the private DNS zone resolves the server name to the private IP

Frequently asked questions

Does this error affect multiple datasets at once?

If multiple datasets connect to the same data source, yes — all of them will fail until the source connectivity is restored.

Can this error be caused by a server migration or rename?

Yes — if the server name, database name, or connection string changed (e.g., during a cloud migration), Power BI still holds the old connection details. Update the connection in Power BI Desktop and republish.

Does this error appear in Power BI Desktop?

Sometimes — if you open the .pbix file and attempt a refresh, Desktop will surface the same connection error. This is useful for debugging without affecting the Service dataset.

Will the error resolve automatically once the source is back online?

Only if it was a temporary outage. The next scheduled refresh will succeed automatically. If the connection string changed or credentials expired, manual intervention is needed.

Source · learn.microsoft.com/en-us/fabric/data-factory/connector-troubleshoot-synapse-sql

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