TDS || Login failed for user 'sa'

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SQL Server

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Unable to connect: 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.

Error Code: -2147217843

Error Source: Microsoft OLE DB Provider for SQL Server

Error Description: Login failed for user 'sa'.

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Root Cause of the error → The error "Login failed for user 'sa'" typically occurs due to incorrect credentials or misconfigurations in SQL Server authentication settings. This issue often arises when the server is set to allow only Windows Authentication, while the login attempt is made using SQL Server Authentication.

Common Causes

1. Incorrect Credentials → The most frequent cause is an incorrect 'sa' username or password. Ensure the credentials are accurate.
2. Authentication Mode Mismatch
   
1. Windows Authentication Mode: If SQL Server is configured to allow only Windows Authentication, attempting to log in with SQL Server Authentication will result in this error.
   
2. Mixed Mode Authentication: Even if the server is set to Mixed Mode (supporting both authentication types), issues can occur if:
1. The 'sa' account is disabled.
   
2. The 'sa' password requires resetting.
   
3. Disabled 'sa' Account → The 'sa' account may be disabled in the SQL Server settings. Administrators should verify its status and enable it if necessary.
4. Insufficient Permissions → In some cases, the 'sa' account may not have the required permissions to access the target database. Ensure the account has the appropriate access rights.

Solution → To resolve the "Login failed for user 'sa'" error in SQL Server, follow these steps on SERVER system:

1. Verify Login Credentials → Ensure that the correct 'sa' username and password are being used.
2. Reset the 'sa' Password → If the password is forgotten or incorrect, reset it by running the following command:
1. Run the below command in Query Express - ALTER LOGIN sa WITH PASSWORD = 'kdk@123456'
   

      

By following these steps, you can successfully restore access to SQL Server using the 'sa' account.

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