System.Data.SqlClient.SqlException (0x80131904): 连接超时时间已到。在尝试使用预登录握手确认时超过了此超时时间。这可能是因为预登录握手失败或服务器未能及时响应。  尝试连接到此服务器时花费的持续时间是 - [Pre-Login] initialization=693；handshake=4383； ---> System.ComponentModel.Win32Exception (0x80004005): 等待的操作过时。<br/>   在 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal&amp; connection)<br/>   在 System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal&amp; connection)<br/>   在 System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal&amp; connection)<br/>   在 System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)<br/>   在 System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)<br/>   在 System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)<br/>   在 System.Data.SqlClient.SqlConnection.Open()<br/>   在 KeLin.ClassManager.ExUtility.DbHelperSQL.ExecuteDataset(String connectionString, CommandType commandType, String commandText, SqlParameter[] commandParameters)<br/>   在 KeLin.WebSite.Default.Page_Load(Object sender, EventArgs e)<br/>ClientConnectionId:614f4636-f891-4a55-b5e1-f798bd999303<br/>Error Number:-2,State:0,Class:11