Laravel Socialite LinkedIn Error (Unable to retrieve access token: appid/redirect uri/code verifier does n (truncated...))

Question

I'm currently working on a Laravel Web-App and trying to use socialite/linkedin, I've tried a lot of things on the internet, playing around whether it should be stateless or not, if it should be linkedin or linkedin-openid, but the one extends the other so it doesn't make a difference. And I can't progress further because I'm only getting the error:

Client error: `POST https://www.linkedin.com/oauth/v2/accessToken` resulted in a `400 Bad Request` response: {"error":"invalid_request","error_description":"Unable to retrieve access token: appid/redirect uri/code verifier does n (truncated...)

My code will be below here, and don't tell me some simple things like changing to -openid or so, it doesn't work. I also have the correct permissions set up in the LinkedIn developer panel, it's all like in the documentation.

<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use App\Models\User;
use Laravel\Socialite\Facades\Socialite;

class SocialiteController extends Controller
{
    public function redirect($provider): \Symfony\Component\HttpFoundation\RedirectResponse
    {
        if (! in_array($provider, $this->getAllowedProviders())) {
            abort(400);
        }

        return Socialite::driver($provider)->redirect();
    }

    public function callback($provider): \Illuminate\Http\RedirectResponse
    {
        if (! in_array($provider, $this->getAllowedProviders())) {
            abort(400);
        }

        $socialiteUser = Socialite::driver($provider)
            ->stateless()
            ->user();

        $user = User::updateOrCreate(
            [
                'provider' => $provider,
                'provider_id' => $socialiteUser->getId(),
            ],
            [
                'name' => $socialiteUser->getName(),
                'email' => $socialiteUser->getEmail(),
                'provider' => $provider,
                'provider_id' => $socialiteUser->getId(),
            ]
        );

        auth()->login($user, true);

        $user->email_verified_at = now();
        $user->save();

        return redirect()->intended('/');
    }

    /**
     * @return string[]
     */
    private function getAllowedProviders(): array
    {
        return ['google', 'linkedin'];
    }
}

I expect the LinkedIn OAuth via laravel/socialite to work flawlessly.