You cannot send the same attribute name multiple times in the same request, the latest will overwrite the previous values. So if you remove the .* from the validations you will be able to validate the data, but that will validate just the last item..
So you can group them like this for example:
{students: [{name: 'Mark', 'classes': 5}, {name: 'John', 'classes': 10}]}
and then validate them:
$rules = [
'students.*.name' => 'required|max:10',
'students.*.classes' => 'required|max:50',
];