Joomla a MSSQL problém

$serverName = "localhost\sqlexpress"; //serverName\instanceName
// Since UID and PWD are not specified in the $connectionInfo array,
// The connection will be attempted using Windows Authentication.
$connectionInfo = array( "Database"=>"testdb");
$conn = sqlsrv_connect( $serverName, $connectionInfo);
if( $conn ) {
     echo "Connection established.<br />";
}else{
     echo "Connection could not be established.<br />";
     die( print_r( sqlsrv_errors(), true));
}

Could not connect to the database. Connector returned number: Database sqlsrv_connect failed, Array ( [0] => Array ( [0] => 08001 [SQLSTATE] => 08001 [1] => 2 [code] => 2 [2] => [Microsoft][ODBC Driver 13 for SQL Server]Named Pipes Provider: Could not open a connection to SQL Server [2]. [message] => [Microsoft][ODBC Driver 13 for SQL Server]Named Pipes Provider: Could not open a connection to SQL Server [2]. ) [1] => Array ( [0] => HYT00 [SQLSTATE] => HYT00 [1] => 0 [code] => 0 [2] => [Microsoft][ODBC Driver 13 for SQL Server]Login timeout expired [message] => [Microsoft][ODBC Driver 13 for SQL Server]Login timeout expired ) [2] => Array ( [0] => 08001 [SQLSTATE] => 08001 [1] => 2 [code] => 2 [2] => [Microsoft][ODBC Driver 13 for SQL Server]A network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online. [message] => [Microsoft][ODBC Driver 13 for SQL Server]A network-related or instance-specific error has occurred while establishing a connection to SQL Server. Server is not found or not accessible. Check if instance name is correct and if SQL Server is configured to allow remote connections. For more information see SQL Server Books Online. ) )