call a model function inside middleware and check authentication in laravel

Question

i've two models, Admin.php & Role.php. there are three tables admins , roles & a pivot table admins_roles. there are two roles in my application, notary & title_officer. i've created middlewares to check the admins according to their roles and redirect them to intended url. but when an authenticated admin logs in, there is only blank page i can see, instead of redirected dashboard. there is no error my application is showing. it's just showing me blank page. how can i fix it ?

Notary middleware ->

<?php

namespace App\Http\Middleware;

use Closure;
use Auth;

class Notary
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        if(Auth::check() && Auth::user()->role()){
            return $next($request);
        }else{
            return redirect()->back();
        }
    }
}

Officer middleware ->

<?php

namespace App\Http\Middleware;

use Closure;
use Auth;

class Officer
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        if(Auth::check() && Auth::user()->role()){
            return $next($request);
        }else{
            return redirect()->back();
        }
    }
}

Admin model ->

<?php

namespace App;

use Illuminate\Notifications\Notifiable;
use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;

class Admin extends Authenticatable
{
    use Notifiable;

    protected $guard = 'admin';

    protected $fillable = [
        'name', 'email', 'password',
    ];

    protected $hidden = [
        'password', 'remember_token',
    ];

    public function role()
    {
        return $this->belongsToMany('App\Role','admins_roles');
    }
}

Role model ->

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Role extends Model
{
    public function admins()
    {
        return $this->belongsToMany('App\Admin','admins_roles');
    }
}

the route i'm using the officer middleware ->

Route::resource('order', 'BackendController')->middleware('officer');