Hi all, I'm new to everything website related, could someone please help me??   I have a website made in ASP.Net using Visual Studio 2010 with 3.5 framework. The site seems to be working fine, except for pages that contain a datagrid linked to my database, database1.mdf in the /app_data folder.   I get this: No such host is known   Description: HTTP 500. Error processing request.   Stack Trace:        System.Net.Sockets.SocketException: No such host is known   at System.Net.Dns.GetHostByName (System.String hostName) [0x00000] in :0    at System.Net.Dns.GetHostEntry (System.String hostNameOrAddress) [0x00000] in :0    at System.Net.Dns.GetHostAddresses (System.String hostNameOrAddress) [0x00000] in :0    at System.Net.Sockets.UdpClient.Connect (System.String hostname, Int32 port) [0x00000] in :0    at System.Net.Sockets.UdpClient..ctor (System.String hostname, Int32 port) [0x00000] in :0    at System.Data.SqlClient.SqlConnection+SqlMonitorSocket..ctor (System.String ServerName, System.String InstanceName) [0x00000] in :0    at System.Data.SqlClient.SqlConnection.DiscoverTcpPortViaSqlMonitor (System.String ServerName, System.String InstanceName) [0x00000] in :0    at System.Data.SqlClient.SqlConnection.ParseDataSource (System.String theDataSource, System.Int32& thePort, System.String& theServerName) [0x00000] in :0    at System.Data.SqlClient.SqlConnection.Open () [0x00000] in :0    at System.Data.Common.DbDataAdapter.Fill (System.Data.DataSet dataSet, Int32 startRecord, Int32 maxRecords, System.String srcTable, IDbCommand command, CommandBehavior behavior) [0x00000] in :0    at System.Data.Common.DbDataAdapter.Fill (System.Data.DataSet dataSet, System.String srcTable) [0x00000] in :0    at (wrapper remoting-invoke-with-check) System.Data.Common.DbDataAdapter:Fill (System.Data.DataSet,string)   at System.Web.UI.WebControls.SqlDataSourceView.ExecuteSelect (System.Web.UI.DataSourceSelectArguments arguments) [0x00000] in :0     This page is here : http://rodd.heliohost.org/Dogs.aspx   Like I said, I'm completely new to this and don't know what this error means or what I can do, so any help would be greatly appreciated.   Thanks in advance