SQL Server Connection Problems

Things to check when clients are having issues with software connecting to a remote instance of SQL Server:

Within SQL Server Configuration Manager, are the TCP/IP and Named Pipes protocols enabled under the SQL Server Native Client Configuration and SQL Server Network Configuration sections? If not then enable them. Are the server and client workstations configured to use the same version of the SQL Server native client? The native client should be the same on the client and on the server. Is the SQL Server Native Client installed on the workstation? This is a common oversight that is simple to fix. Just download and install the correct native client (i.e., the same version as that used on the server). You can obtain the SQL Server native client by searching for the SQL Server Feature Pack for your version of SQL Server. Is the database installed and running? Yes, sometimes installations can be complex and require the attachment of a database or the running of a SQL script. Have you check the database is there? Can you connect to the database via ODBC? If not check the following:

Are the SQL Server service and the SQL Browser services running? You can check this via SQL Server Connection Manager.

Are the SQL Server and SQL Server Browser services logged on as NTAUTHORITY\NETWORKSERVICE? If not, stop them change their Log On As property to NT AUTHORITY\NETWORKSERVICE

Is there a firewall running? If there is you will need to add exceptions for TCP/IP on Port 1433, and UDP on Port 1434.

Is the SQL Server running in a virtual environment? If so, try disabling TCP/IP and see if this makes a difference.

Are the SQL Server and client workstations on the same domain? Make sure they are.

Have you installed SQL Server on a domain controller? If so have you created the required NETWORKSERVICE accounts for the SQL Server service and SQL Browser service?

If you have not installed your SQL Server on a domain controller, have you during the install selected user accounts that are local to the computer that do not have network access? If so change the accounts using SQL Server Configuration manager to NETWORKSERVICE.