error php con sqlserver

[kakashi20]

LO HICE ASI :

$sql = "SELECT * FROM NEMPRESA";
$query = sqlsrv_query( $conn, $sql );


while( $row = sqlsrv_fetch_array( $query ) ) {
echo $row['NENOMEMP']."<br />";
}



PERO ME ARROJA EL ERROR:

Warning: sqlsrv_fetch_array() expects parameter 1 to be resource, boolean given in