Microsoft FAQ » Development » MS SQL Server » SQL Server 2008 » Can't connect to SQL server 2008 (error 40 could not open a connection to the SQL Server)

Can't connect to SQL server 2008 (error 40 could not open a connection to the SQL Server)
hello all,

I'm running into this very strange error: I have two servers. both have windows server 2008. They both have SQL server 2008 installed.

I can connect to one of the servers just fine. but I can't connect to the other one.

what I've done so far: SQL browser is running. Also I've enabled TCP/IP in the sql server configuration manager, also I've verified that the server is allowed to recevie incoming connections. I have also even compeltely disabled the Windows server firewall. Below is the message i keep getting.

TITLE: Connect to Server
------------------------------

Cannot connect to SRV1.

------------------------------
ADDITIONAL INFORMATION:

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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 1326)

For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&EvtSrc=MSSQLServer&EvtID=1326&LinkId=20476

Any help would be awesome!
Thanks
CPG

Solution: Can't connect to SQL server 2008 (error 40 could not open a connection to the SQL Server)

I know these are all obvious, but have you checked these:
1.  Is this a default instance of SQL (in which case your "Server Name" above is correct), or is this a named instance?
2.  Are you sure the port is 1434?  Use the SQL Server Config Manager (SQL Native Client, Client Protocols, TCI/IP, Default Port) to verify.
3.  Also try without any port number specified.
4.  Are you sure the username and password are correct?  Try using these credentials in SSMS to verify they work.
Bookmark and Share
Problem: Exchange Migration from SBS 2003 to Exchange 2007   Problem: On Timer Stoppage & Macro Error Handling  
outlook 2000 "TCP/IP connection was unexpectedly terminated by your mail server.  If this problem persists, contact your LAN   Windows Server 2003 Scheduled Tasks Not Running in Background  
email notification when disk space is running low   Active Directory failed to construct a mutual authentication service principal name (SPN) for the domain controller.  
AccessVB:Set Focus on currently selected record   Problem: What's the best design of DNS in AD-Intergrated zone?  
How to insert automatic, sequential numbering on an excel template   Making a chart see a #DIV/0! error as an empty cell  
How can I stop MS Excel from calculating cells.   Pass Through Query Repeatedly Prompting for ODBC Connection information  
Maintenance overlap for database   Problem: Exporting report to .pdf format  
Problem: How can I have a macro execute automatically when data is scanned into a cell?   Problem: Set default line weight, font, etc. in Microsoft PowerPoint 2007  
Modify find/replace dialog box settings   What is the Best Way to Setup Microsoft Access Record Navigation?  
stsadm   Outer join in access