sqlserver2008R2间接性出现无法连接的情况

总是间接性出现，没有固定规律，有没有人碰到过这种情况，求大神指点，帮忙分析下。

错误提示如下

Exception information:
Exception type: SqlException
Exception message: 在与 SQL Server 建立连接时出现与网络相关的或特定于实例的错误。未找到或无法访问服务器。请验证实例名称是否正确并且 SQL Server 已配置为允许远程连接。 (provider: 命名管道提供程序, error: 40 - 无法打开到 SQL Server 的连接)

Thread information:
Thread ID: 101
Is impersonating: False
Stack trace: 在 System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
在 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
在 System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject)
在 System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject)
在 System.Data.SqlClient.SqlInternalConnectionTds.LoginWithFailover(Boolean useFailoverHost, String primaryHost, String failoverHost, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart)
在 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance)
在 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance)
在 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection)
在 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options)
在 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject)
在 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject)
在 System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject)
在 System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
在 System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
在 System.Data.SqlClient.SqlConnection.Open()