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TITLE: Error ------------------------------ A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server

Bhoomi Chauhan 0 Reputation points
2026-02-20T07:27:25.2866667+00:00

TITLE: Error

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) (Microsoft SQL Server, Error: -1)

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  1. Erland Sommarskog 134K Reputation points MVP Volunteer Moderator
    2026-02-20T21:28:30.6233333+00:00

    The error message means that you were not able to connect to the SQL Server instance you specified. There can be any number of reasons for this:

    • SQL Server is not running.
    • You have misspelled the server or instance name.
    • There is no SQL Server instance running on the server you have specified.
    • There is a firewall blocking the connection.

    This list is not exhaustive.

    If you are in a corporate network, you should talk with your IT people or a colleague for the connection details to the SQL Server instance you are supposed to connect.

    If you are on your private laptop, bear in mind that only installing SSMS will not take you anywhere. SSMS is only a tool to talk to SQL Server. You need to download and install SQL Server separately.

    If you want further help, you need to give more details, for instance why you expect the connection to work, and what troubleshooting you have conducted.

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  1. Q&A Assist
    2026-02-20T07:27:37.7066667+00:00
    AI generated content. This question contains an answer created with AI from Q&A Assist. Learn more

    The error message you are encountering indicates that there is a problem establishing a connection to SQL Server. Here are some common reasons and troubleshooting steps:

    1. Instance Name: Verify that the SQL Server instance name is correct. If you installed SQL Server Express, the instance name typically follows the format MACHINENAME\SQLEXPRESS.
    2. SQL Server Service: Ensure that the SQL Server service is running. You can check this in the SQL Server Configuration Manager.
    3. Remote Connections: Check if SQL Server is configured to allow remote connections. This can be done in the SQL Server Management Studio or SQL Server Configuration Manager.
    4. Firewall Settings: If SQL Server is running on a different machine, ensure that any firewalls are configured to allow traffic on the SQL Server port (default is 1433).
    5. Browser Service: Make sure that the SQL Server Browser service is running, especially if you are using named instances.
    6. Network Issues: Check for any network issues that might prevent your application from reaching the SQL Server.

    If you follow these steps and still encounter issues, you may want to refer to the detailed troubleshooting guides available in the Microsoft documentation.

    References:

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