错误消息几乎说明了一切:确保实例名称正确(如果您的 SQL 服务器正在使用实例)并确保您的服务器配置为允许远程连接.

The error message pretty much says it all: make sure the instance name is correct (if your SQL server is using instances) and make sure your server is configured to allow remote connections.

如何配置 SQL Server 以允许远程连接

如何连接到服务器实例