Troubleshoot connectivity issues in SQL Server

Applies to:   SQL Server
Original KB number:   4009936

There are various causes for connectivity issues in SQL Server. This article series helps you troubleshoot the most common SQL Server connectivity issues and describes the tools and methods you can use for troubleshooting.


If multiple SQL Server instances in your environment are impacted, or the issue is intermittent, it usually indicates Windows policy or networking issues. Although this series of articles provides guidance, it may not effectively troubleshoot some specific scenarios.


Before you start troubleshooting, check Recommended prerequisites and checklist for troubleshooting connectivity issues for logs that you should collect to assist with troubleshooting. There's also a list of quick actions to avoid common connectivity errors when working with SQL Server.

Common connectivity issues

Use the following list to navigate to the appropriate article page for detailed troubleshooting steps for your scenario:

Tools and methods that help you troubleshoot connectivity issues

The following articles provide details for various tools and procedures to troubleshoot different connectivity errors:

See also

CSS SQL Connectivity Wiki