laravel 5.2 Restfull Api with admin panel stop working suddenly - laravel-5

Question

I developed admin panel to add,edit,delete users in my website with Restfull Api. edit and delete work fine but add not.
when I add user it may work or this error may appear
The localhost page isn’t working
localhost is currently unable to handle this request.
This is my routes
Route::resource('admin/users','AdminUser');
This is store function in Admin user resource
public function store(Request $request)
{
//rules
$rules = array(
'name' => 'required',
'email' => 'required|email',
'password' => 'required|min:6|confirmed',
'password_confirmation' => 'required|min:6'
);
/*
validate the data user
**/
$validator = Validator::make($request->all(),$rules);
if ($validator->fails()) {
return view('admin.User.create_user')
->withErrors($validator)
->withInput(['page' => 'home']);
}
/*
Store the data user in the database
**/
$user = new User;
$user->name =$request->input('name');
$user->email = $request->input('email');
$user->password=bcrypt($request->input('password'));
$user->role='user';
$user->save(); //error here
//redirect
return redirect('admin/users')->with('message', 'Successfully added user!');
}
And this is create_user.blade.php
#extends('layouts.layout')
#section('content')
<section id="advertisement">
<div class="container">
<img src="{{asset('images/shop/advertisement.jpg')}}" alt="" />
</div>
</section>
<section>
<div class="container">
<div class="row">
<div class="col-sm-3">
<div class="left-sidebar">
#include('shared.sidebaradmin')
</div>
</div>
<div class="features_items"><!--features_items-->
<h2 class="title text-center">Add New Product</h2>
#if (count($errors) > 0)
<div class="alert alert-danger">
<ul>
#foreach ($errors->all() as $error)
<li>{{ $error }}</li>
#endforeach
</ul>
</div>
#endif
{{ Form::open(array('url' => 'admin/users')) }}
<div class="form-group">
{{ Form::label('name', 'Name') }}
{{ Form::text('name',null, array('class' => 'form-control')) }}
</div>
<div class="form-group">
{{ Form::label('email', 'Email') }}
{{ Form::email('email',null, array('class' => 'form-control')) }}
</div>
<div class="form-group">
{{ Form::label('password', 'Password') }}
{{ Form::password('password', array('class' => 'form-control')) }}
</div>
<div class="form-group">
{{ Form::label('password_confirmation', 'Confirm Password') }}
{{ Form::password('password_confirmation', array('class' => 'form-control')) }}
</div>
{{ Form::submit('Add a new user !', array('class' => 'btn btn-primary')) }}
{{ Form::close() }}
</div><!--features_items-->
</div>
</div>
</section>
#endsection