 <p>I would suggest ensuring that you have the correct connection details. The easiest way I can think of would be :</p> <ol> <li>Create a new text file ( f.e. connection.txt )</li> <li>Rename '.txt' to '.udl'</li> <li>Double-click the created connection.udl file</li> <li>Provide all the required connection details, hit 'Test connection' button</li> <li>If it works, hit 'OK' button, open the file with Notepad - connection string will be inside of your connection.udl file. If it doesn't work - you need to find out proper server details ( check instance name, port number, if your user has the correct permissions )</li> </ol>