"The certificate chain was issued by an authority that is not trusted" error after upgrading SNAC applications
Support for the SQL Server Native Client 11.0 (SNAC) as a driver for database applications ended on July 12, 2022. Any applications that use the SNAC 11.0 must be updated to use newer versions of the drivers (see Download ODBC Driver for SQL Server and Download Microsoft OLE DB Driver for SQL Server). This article describes an issue that occurs when you upgrade your SNAC 11.0 application to use either Microsoft OLE DB Driver 19 for SQL Server or Microsoft ODBC Driver 18.x for SQL Server.
- Upgraded to Microsoft OLE DB Driver 19 for SQL Server
- Upgraded to Microsoft ODBC Driver 18.x for SQL Server
If you recently upgraded your SQL Server Native Client 11.0 (Provider=SQLNCLI11) application to use Microsoft OLE DB Driver 19 for SQL Server (Provider=MSOLEDBSQL19), you might receive error messages that resemble the following messages:
[Microsoft OLE DB Driver 19 for SQL Server]: Client unable to establish connection
[Microsoft OLE DB Driver 19 for SQL Server]: SSL Provider: The certificate chain was issued by an authority that is not trusted.
These errors occur if both the following conditions are true:
The Force encryption setting for the SQL Server instance is set to No.
The client connection string doesn't explicitly specify a value for encryption property, or the Encryption option wasn't explicitly set or updated in the DSN.
The error occurs because of a change in the default behavior of the client drivers. Older versions of client drivers are designed to assume that data encryption is OFF by default. The new drivers assume this setting to be ON by default. Because data encryption is set to ON, the driver tries to validate the server's certificate and fails.
Solution 1: Use Microsoft OLE DB Driver for SQL Server 18.x. You can download the driver from Release notes for the Microsoft OLE DB Driver for SQL Server.
Solution 2: If the application connection string property already specifies a value of Yes or Mandatory for the Encrypt/Use Encryption for Data setting, change the value to No or Optional. For example, Use Encryption for Data=Optional. If the connection string doesn't specify any value for Encrypt/Use Encryption for Data, add Use Encryption for Data=Optional to the connection string. For more information, see Encryption and certificate validation.
Solution 3: Add
;TrustServerCertificate=trueto the connection string. This will force the client to trust the certificate without validation.
Currently, MSOLEDBSQL19 prevents the creation of linked servers without encryption and a trusted certificate (a self-signed certificate is insufficient). If linked servers are required, use the existing supported version of MSOLEDBSQL.