[sql server] A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible.

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• 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 28 - server doesn't support requested protocol
• the certificate chain was issued by an authority that is not trusted

今天在一个环境上装了sql server, 想在开发环境使用ssms远程连接该server.输入完登录信息后发现登录不了:

查阅网上资料后得到如下信息:

1. 确定sql browser service的状态是running.
2. 在server所在的环境上使用ssms连接server, 右键点击server>properties>connection>remote connection确定check了.
   
3. 确定sql server service的端口号是否被防火墙屏蔽了. (我是直接关闭防火墙了)
   这些都检查完后,再次输入信息发现错误不是之前的了:

provider sql network interfaces error 28 - server doesn't support requested protocol

依旧查阅网上资料后, 需要打开server所在的环境的sql server connection manager, 按照下图改一些配置:

将TCP/IP enable

之后再次login, 依旧发现无法连接, 但是错误变成了:

the certificate chain was issued by an authority that is not trusted.

全都改完后,则可以顺利远程连接sql server了.

参考资料

• https://stackoverflow.com/questions/17615260/the-certificate-chain-was-issued-by-an-authority-that-is-not-trusted-when-conn
• https://dba.stackexchange.com/questions/173785/the-certificate-chain-was-issued-by-an-authority-that-is-not-trusted
• https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/troubleshoot-connecting-to-the-sql-server-database-engine?view=sql-server-2017
• https://stackoverflow.com/questions/13238219/sql-server-express-cannot-connect-error-28-server-doesnt-support-requested-p

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希望以上内容能够帮助到遇到同样问题的你.如有其它思路可以随时联系我.