Laravel Middleware error: Argument #1 ($content) must be of type ?string, Illuminate\Routing\Redirector given

I have this middleware in my project, that sometimes, gives me some problems on my live server, and I don't know why, but just sometimes, and not all the times that it is triggered. This is the error:

Symfony\Component\HttpFoundation\Response::setContent(): Argument #1 ($content) must be of type ?string, Illuminate\Routing\Redirector given

The error is triggered by the return $next($request);, bellow is my middleware:

<?php
namespace App\Http\Middleware;
use Closure;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use App\Models\Event;
class EventOwner
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure(\Illuminate\Http\Request): (\Illuminate\Http\Response|\Illuminate\Http\RedirectResponse)  $next
     * @return \Illuminate\Http\Response|\Illuminate\Http\RedirectResponse
     */
    public function handle(Request $request, Closure $next)
    {
        if(isset($request["id_event"])){
            $event_id = $request["id_event"];
            $events = Event::where('id', $event_id)->where('user_id', Auth::user()->id)->first();
            if(isset($events)){
                if($events->id == $event_id){
                    return $next($request);
                }else{
                    $message = '401 - NOT AUTHORIZED';
                    return response(view('errors.not-auth', compact('message')), 401);
                }
            }else{
                $message = '401 - NOT AUTHORIZED';
                return response(view('errors.not-auth', compact('message')), 401);
            }
        }
    }
}

I already changed my return to a return redirect()->route('register');, to return a redirector object, but nothing happened.

I tried to improve my code too, I changed the code to this:

 public function handle(Request $request, Closure $next)
    {
            $event_id = $request["id_event"];
            if (!$event_id) {
               abort(404);
            }
            $events = Event::where('id', $event_id)->where('user_id', Auth::user()->id)->first();
            if ($events->isEmpty()) {
              $message = '401 - NOT AUTHORIZED';
              return response()->view('errors.not-auth', compact('message'), 401); // Create response with error view
            }
            return $next($request);
    }

although this is a good improvement, I still don't know how to replicate the error, or what triggered the error.

I tried to php artisan config:clear in my live server but, again, I don't know if it works, because I cant replicate the error.

Can someone help me fix this issue, and help me find what triggered the error? Thank you in advance.

Thats not a middleware related problem it is router/controller level problem. After your middleware is finished you do some redirects at your router/controller and your return redirect(); is probably empty. Check your redirects after middleware.