A connection was successfully established with the server, but then an error occurred during the pre

[joshua1990]

Report_WriteToDataDestination: There was a problem refreshing the dataflow: 

'Couldn't refresh the entity because of an issue with the mashup document MashupException.Error: Microsoft SQL: A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.) Details: Reason = DataSource.Error;DataSourceKind = Lakehouse;DataSourcePath = Lakehouse;DataSourceKind.2 = SQL;DataSourcePath.2 = XXX.datawarehouse.fabric.microsoft.com;DataflowsStagingLakehouse1;Message = A connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.);ErrorCode = -2146232060;Number = 121;Class = 20;State = 0;Microsoft.Data.Mashup.Error.Context = System GatewayObjectId: XXX'. Error code: Mashup Exception Data Source Error. (Request ID: XXX).

I see no issues with the gateways in the dataflow. Lakehouse and Datafloe Gateway are on-premise gateways.

[v-lgarikapat]

Hi @joshua1990 

Thanks for reaching out to the Microsoft fabric community forum.

To troubleshoot the pre-login handshake error in your dataflow refresh, start by checking for network issues like unstable connectivity between the on-premise gateway and the SQL server. Ensure that the firewall and required ports for SQL communication are open and not blocking traffic. Restart the on-premise gateway to clear any temporary issues and verify that your SQL server allows remote connections with the correct TLS settings. If encryption is involved, double-check authentication methods and certificates to ensure they are valid and updated. Consider increasing timeout settings if semaphore timeout errors persist. Run the dataflow on another server or gateway instance to see if the problem is isolated. Finally, check SQL Server logs for more specific error details and review any recent changes in the environment that could have introduced this issue.

Timeout expired messages when connecting to SQL Server - SQL Server | Microsoft Learn

Solved: DataSource.Error: Microsoft SQL: A connection was ... - Microsoft Fabric Community

Solved: Re: SQL EndPoint - Successfuly connected but erro... - Microsoft Fabric Community

If this post helped resolve your issue, please consider giving it Kudos and marking it as the Accepted Solution. This not only acknowledges the support provided but also helps other community members find relevant solutions more easily.

We appreciate your engagement and thank you for being an active part of the community.

Best regards,
LakshmiNarayana

[v-lgarikapat]

Hi @joshua1990 ,

If your issue has been resolved, please consider marking the most helpful reply as the accepted solution. This helps other community members who may encounter the same issue to find answers more efficiently.

If you're still facing challenges, feel free to let us know we’ll be glad to assist you further.

Looking forward to your response.

Best regards,
LakshmiNarayana.

[v-lgarikapat]

Hi @joshua1990 ,

If your issue has been resolved, please consider marking the most helpful reply as the accepted solution.

This helps other community members who may encounter the same issue to find answers more efficiently.

If you're still facing challenges, feel free to let us know we’ll be glad to assist you further.

Looking forward to your response.

Best regards,
LakshmiNarayana.

[v-lgarikapat]

Hi @joshua1990 ,

As we haven't heard back from you, we are closing this thread. If you are still experiencing the issue, please feel free to create a new thread we’ll be happy to assist you further.

Thank you for your patience and support.

If you found our response helpful, please mark it as Accepted Solution so others with similar queries can find it easily.

Best Regards,

Lakshmi Narayana