[PHP] Can't connect mssql server

<?php
//
ini_set('display_errors','On');
error_reporting(E_ALL | E_STRICT);

$serverName = "WIN-TKQHRGCY678\SQLEXPRESS"; //serverName\instanceName


$connectionInfo = array( "Database"=>"dbTest", "UID"=>"WIN-TKQHRGCY678\MyAccount", "PWD"=>"123456z");
$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));
}

?>

Array ( [0] => Array ( [0] => 28000 [SQLSTATE] => 28000 [1] => 18456 [code] => 18456 [2] => [Microsoft][SQL Server Native Client 10.0][SQL Server]Login failed for user 'WIN-TKQHRGCY678\MyAccount'. [message] => [Microsoft][SQL Server Native Client 10.0][SQL Server]Login failed for user 'WIN-TKQHRGCY678\MyAccount'. ) [1] => Array ( [0] => 28000 [SQLSTATE] => 28000 [1] => 18456 [code] => 18456 [2] => [Microsoft][SQL Server Native Client 10.0][SQL Server]Login failed for user 'WIN-TKQHRGCY678\MyAccount'. [message] => [Microsoft][SQL Server Native Client 10.0][SQL Server]Login failed for user 'WIN-TKQHRGCY678\MyAccount'. ) )