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SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified

Hi

I am receiving an intermittent error as described in the thread title. I have checked several other threads and the commons solutions seem to be...

check the SQL browser service is running

check the spelling of the instance name

check that the correct UDP port is open on the firewall

All of the above are ok in my case but where my case differs is that the error is intermittent - restarting the server solves the problem but sooner or later, it reocurrs. This specificaly relates to an asp.net application - even when I start getting the error, the web app runs fine over the network but running it in debug or testing / creating connection strings gives error 26. I am all out of ideas with this and it's really not convenient to shut down the server in the middle of a working day. I intended to include the full error text at the end of this question but in the time it has taken me to type this, it has started working again (what the ____!!??!). I am running SQL Server 2008 Express with Visual Studio 2010. Any help would be greatly appreciated.

Regards

Steve

 Update: full error text below...

Server Error in '/' Application.
--------------------------------------------------------------------------------

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: 26 - Error Locating Server/Instance Specified)
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: 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: 26 - Error Locating Server/Instance Specified)

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. 

Stack Trace:


[SqlException (0x80131904): 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: 26 - Error Locating Server/Instance Specified)]
   System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +5009598
   System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning() +234
   System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity) +341
   System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, SqlConnection owningObject) +129
   System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, TimeoutTimer timeout) +270
   System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, TimeoutTimer timeout, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) +195
   System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) +232
   System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) +185
   System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) +33
   System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) +524
   System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) +66
   System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) +479
   System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) +108
   System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) +126
   System.Data.SqlClient.SqlConnection.Open() +125
   System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +123
   System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +319
   System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, String srcTable) +92
   System.Web.UI.WebControls.SqlDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +1618
   System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +21
   System.Web.UI.WebControls.DataBoundControl.PerformSelect() +143
   System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +74
   System.Web.UI.WebControls.GridView.DataBind() +4
   System.Web.UI.WebControls.BaseDataBoundControl.EnsureDataBound() +66
   System.Web.UI.WebControls.CompositeDataBoundControl.CreateChildControls() +75
   System.Web.UI.Control.EnsureChildControls() +102
   System.Web.UI.Control.PreRenderRecursiveInternal() +42
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2496

 


--------------------------------------------------------------------------------
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1

 

6 Answers Found

 

Answer 1

The SQL Protocols team keeps a pretty active blog that is often helpful.  For example:

http://blogs.msdn.com/b/sql_protocols/archive/2007/05/13/sql-network-interfaces-error-26-error-locating-server-instance-specified.aspx

Perhaps you have already read this, since it mentions the three common answers that you have seen.  However, because of the intermittent problem that you face, I would suspect problem 3.

3) Make sure the server machine is reachable, e.g, DNS can be resolve correctly, you are able to ping the server (not always true).

I suspect that there are some intermittent networking problems that are causing you difficulty.  This may mean getting the network people (if there are some) to monitor and trace the network components.  Then they should have information to correlate with you next outage.

FWIW,
RLF

 

Answer 2

Thanks for the reply Russell. Since I last restarted my server, this problem hasn't resurfaced although I expect it will happen sooner or later. I'll try your suggestions when this next occurs.

Regards

Steve

 

Answer 3

Any more ideas on this? The problem occurred again this morning so I tried pinging the server and had no issues doing so. As stated above, the production installation of the application that runs over our network (as our local intranet) works fine - I am only getting this error when debugging from Visual Studio 2010. Restarting the server seems to fix the issue but only for a couple of days or so. Also, I have no doubt that if I keep trying throughout the day, it will suddenly be working again temporarily without me making any configuration changes. I am completely out of ideas here, any help would be greatly appreciated.

Reagrds

Steve

 

Answer 4

Steve, I have not the personal experience.  But "Mister James" had a similar experience that he blogged about here:

http://theycallmemrjames.blogspot.com/2010/01/sql-network-interfaces-error-26-error.html

His problem, found under "Finally a Solution" was using the "default constructor" in a couple of places, which actually (in his case) pointed to a different server.

Hope it helps,
RLF

 

Answer 5

Any more ideas on this? The problem occurred again this morning so I tried pinging the server and had no issues doing so. As stated above, the production installation of the application that runs over our network (as our local intranet) works fine - I am only getting this error when debugging from Visual Studio 2010. Restarting the server seems to fix the issue but only for a couple of days or so. Also, I have no doubt that if I keep trying throughout the day, it will suddenly be working again temporarily without me making any configuration changes. I am completely out of ideas here, any help would be greatly appreciated.

Reagrds

Steve


Since this issue only happens while debuging asp.net applications from Visual Studio, I would like suggest opening a case with Microsoft CSS (http://support.microsoft.com).

Thanks,
Chunsong

 

Answer 6

Thanks for the reply Chunsong. I tried this but when I entered my product key, the site said 'all non chargeable support calls have already been used'. Seems strange seeing as I have only contacted them once since purchase. However, I probably should have posted this in the VS forums.

Thanks

Steve

 
 
 

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