Forum Discussion
Power BI SQL Connection Timeout – Pre-login Handshake Failed
Hi everyone,
I’m running into a persistent connection issue when trying to connect Power BI Desktop to a SQL Server database.
Error Details:
Microsoft SQL: Connection Timeout Expired. The timeout period elapsed while attempting to consume the pre-login handshake acknowledgement. This could be because the pre-login handshake failed or the server was unable to respond back in time. The duration spent while attempting to connect to this server was - [Pre-Login] initialization=29159; handshake=26353;
What I’ve Observed
The same SQL Server instance connects successfully using SQL Server Management Studio (SSMS) and Tableau with the same credentials and server details.
The issue occurs only in Power BI Desktop.
It seems to fail during the pre-login handshake phase, possibly related to timeout or TLS negotiation.
What I’ve Tried
Verified SQL Server instance is running and accessible.
Confirmed correct server name, port, and authentication settings in Power BI.
Checked that firewall and port 1433 are open.
Network connection is stable (no VPN drops).
Increased the connection timeout value — no improvement.
Restarted Power BI Desktop and the SQL Server service.
Environment Details
Power BI Desktop version: 2.142.928.0 (64-bit, April 2025)
ODBC Driver: ODBC Driver 17 for SQL Server (2017.1710.06.01)
Question
Has anyone else experienced this pre-login handshake timeout issue with Power BI, even though SSMS and Tableau can connect to the same database successfully?
Any suggestions on resolving this — whether it’s related to the Power BI SQL connector, driver version, TLS settings, or network timeout configuration — would be greatly appreciated.
This Power BI SQL Server connection timeout during the pre-login handshake is almost always related to mismatches in TLS/SSL settings, driver compatibility, firewall port handling, or certificate issues. Here are concise steps to troubleshoot and resolve based on recent user reports and official solutions:
Step-by-Step Solution
Verify SQL Server Access
Use ping <SQLServerName> and telnet <SQLServerName> 1433 on your machine to confirm connectivity.
Check Driver and Power BI Version
Make sure Power BI Desktop and your SQL ODBC driver (try ODBC Driver 18 for SQL Server if possible) are updated to the latest versions.
Review TLS/SSL Settings
If SQL Server is set to “Force Encryption” and using a self-signed certificate, Power BI may fail to connect if the certificate cannot be verified.
Try disabling “Force Encryption” on SQL Server as a test (consult with your DBA).
Disable Encryption Temporarily
In Power BI, append ;Encrypt=False to the server connection string.
Example: Server=yourserver;Encrypt=False
If this works, SSL issues are likely.
Use Fully Qualified Domain Name (FQDN)
Ensure you are using the FQDN matching the SQL Server certificate’s CN or SAN fields in your Power BI connection details.
Increase Timeout in Power BI
Go to Options > Data Load > Timeouts and set timeout to 300 seconds.
Check Windows Firewall and SQL Ports
Verify TCP port 1433 and UDP port 1434 are open and correctly routed on both local and server firewalls.
Check Network Stability/Latency
Test on a wired network, not just Wi-Fi, to rule out intermittent network drops.
Restart SQL Server and Power BI Desktop
Sometimes connection resets resolve handshake issues.
6 Replies
This Power BI SQL Server connection timeout during the pre-login handshake is almost always related to mismatches in TLS/SSL settings, driver compatibility, firewall port handling, or certificate issues. Here are concise steps to troubleshoot and resolve based on recent user reports and official solutions:
Step-by-Step Solution
Verify SQL Server Access
Use ping <SQLServerName> and telnet <SQLServerName> 1433 on your machine to confirm connectivity.
Check Driver and Power BI Version
Make sure Power BI Desktop and your SQL ODBC driver (try ODBC Driver 18 for SQL Server if possible) are updated to the latest versions.
Review TLS/SSL Settings
If SQL Server is set to “Force Encryption” and using a self-signed certificate, Power BI may fail to connect if the certificate cannot be verified.
Try disabling “Force Encryption” on SQL Server as a test (consult with your DBA).
Disable Encryption Temporarily
In Power BI, append ;Encrypt=False to the server connection string.
Example: Server=yourserver;Encrypt=False
If this works, SSL issues are likely.
Use Fully Qualified Domain Name (FQDN)
Ensure you are using the FQDN matching the SQL Server certificate’s CN or SAN fields in your Power BI connection details.
Increase Timeout in Power BI
Go to Options > Data Load > Timeouts and set timeout to 300 seconds.
Check Windows Firewall and SQL Ports
Verify TCP port 1433 and UDP port 1434 are open and correctly routed on both local and server firewalls.
Check Network Stability/Latency
Test on a wired network, not just Wi-Fi, to rule out intermittent network drops.
Restart SQL Server and Power BI Desktop
Sometimes connection resets resolve handshake issues.
Hi prabavathym ,
What authentication method are you using? Is it Microsoft Authentication or SQL Authentication? Can you try switching to a different authentication method and see if things are different? Also, you could probably try connecting to a different SQL Server instance (or create a local instance) and check if the issue exists for all SQL Server instances or is it for just this server instance?
Hope it helps!Thanks for the quick response!
I’m currently using SQL Authentication to connect.
Really helpful steps — I’ll try updating the driver and checking the TLS/encryption settings. Will share how it goes.
Hi prabavathym ,
May I know if there are any updates regarding the driver update and TLS/encryption settings? Please let us know how it went, and if you need any further assistance, we’re here to help.
Thank you alish_b Shubham_rai955 for your prompt response.
Regards,
Yugandhar.
Hi prabavathym ,
Could you please let us know whether the issue has been resolved on your end? Your feedback can assist others in the community who may encounter a similar problem.
