Laravel Auth from external api user

Question

I am following this stackOverflow post and I am using laravel 5.8.38. I did everything suggested here, but I am getting error,

Call to undefined method App\Auth\ApiUserProvider::check()

on,

vendor/laravel/framework/src/Illuminate/Auth/Middleware/Authenticate.php

foreach ($guards as $guard) {
        if ($this->auth->guard($guard)->check()) {
            return $this->auth->shouldUse($guard);
        }
    }

What am I doing wrong ?