What causes UserErrorSqlFailedToConnect?

SQL Server is not configured to allow TCP/IP connections (check SQL Server Configuration Manager). The SQL Server Browser service is stopped, preventing named instance resolution. TLS certificate mismatch between the ADF integration runtime and the SQL server. SQL Server is configured on a non-default port and the linked service uses port 1433

How do I fix UserErrorSqlFailedToConnect?

On the SQL Server machine, open SQL Server Configuration Manager and verify TCP/IP is enabled for the instance.. Verify the SQL Server Browser service is running if using a named instance (e.g., SERVER\INSTANCE).. If using a non-default port, update the linked service connection string to include the correct port.. Check that the TLS/SSL certificate presented by SQL Server is trusted by the integration runtime machine.. Run a connectivity test from the IR machine: Test-NetConnection -ComputerName -Port 1433.

High severitydata source

Power BI Refresh Error:
UserErrorSqlFailedToConnect

What does this error mean?

ADF resolved the SQL server hostname but could not complete the TCP connection or TLS handshake. The server is reachable but the connection is refused or dropped.

Common causes

1SQL Server is not configured to allow TCP/IP connections (check SQL Server Configuration Manager)
2The SQL Server Browser service is stopped, preventing named instance resolution
3TLS certificate mismatch between the ADF integration runtime and the SQL server
4SQL Server is configured on a non-default port and the linked service uses port 1433

How to fix it

1On the SQL Server machine, open SQL Server Configuration Manager and verify TCP/IP is enabled for the instance.
2Verify the SQL Server Browser service is running if using a named instance (e.g., SERVER\INSTANCE).
3If using a non-default port, update the linked service connection string to include the correct port.
4Check that the TLS/SSL certificate presented by SQL Server is trusted by the integration runtime machine.
5Run a connectivity test from the IR machine: Test-NetConnection -ComputerName <sql-host> -Port 1433.

Frequently asked questions

Does this error affect all pipeline runs or just the current one?

Depends on the root cause. A persistent misconfiguration fails every run; a transient issue may resolve on retry. Check the run history.

Can this error appear in Azure Data Factory and Microsoft Fabric pipelines?

Yes — the same connector errors appear in both ADF and Fabric Data Factory pipelines.

How do I see the full error detail for an ADF pipeline failure?

In ADF Monitor, click the failed run, then the failed activity. The detail pane shows the error code, message, and sub-error codes.

Will downstream Power BI datasets be affected when an ADF pipeline fails?

Yes — a dataset refreshing after the pipeline will use stale data or fail if the target table was cleared. The Power BI refresh may succeed while serving wrong data.

Official documentation: https://learn.microsoft.com/en-us/azure/data-factory/connector-troubleshoot-sql