Error Getting data through API Laravel 5.8

Good day all, Please I need some help, for some reason, I can't get data through API I get this error

            $this->data = $data->toJson($this->encodingOptions);
        } elseif ($data instanceof JsonSerializable) {
            $this->data = json_encode($data->jsonSerialize(), $this->encodingOptions);
        } elseif ($data instanceof Arrayable) {
            $this->data = json_encode($data->toArray(), $this->encodingOptions);
        } else {
            $this->data = json_encode($data, $this->encodingOptions);
        }
 
        if (! $this->hasValidJson(json_last_error())) {
            throw new InvalidArgumentException(json_last_error_msg());
        }
 
        return $this->update();
    }
 
    /**
     * Determine if an error occurred during JSON encoding.
     *
     * @param  int  $jsonError
     * @return bool
     */
    protected function hasValidJson($jsonError)
    {
        if ($jsonError === JSON_ERROR_NONE) {
            return true;
        }
 
        return $this->hasEncodingOption(JSON_PARTIAL_OUTPUT_ON_ERROR) &&
                    in_array($jsonError, [
                        JSON_ERROR_RECURSION,
Arguments
"Malformed UTF-8 characters, possibly incorrectly encoded"

Here is my API route

<?php

use Illuminate\Http\Request;

/*
|--------------------------------------------------------------------------
| API Routes
|--------------------------------------------------------------------------
|
| Here is where you can register API routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| is assigned the "api" middleware group. Enjoy building your API!
|
*/

Route::middleware('auth:api')->get('/user', function (Request $request) {
    return $request->user();
});

Route::get('projects', 'API\ProjectsController@index');

and this is my Api/ProjectsController

<?php

namespace App\Http\Controllers\Api;

use App\Project;
use Illuminate\Http\Request;
use App\Http\Controllers\Controller;

class ProjectsController extends Controller
{
    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index()
    {
        //
        return Project::latest()->paginate(10);
    }

I tried resources I get the root URL HTML content

I appreciate your help