Doctrine EntityManager persist() fails on new entity with relationships

Question

I have a Symfony application using Doctrine ORM. When creating a new Temp entity with relationships and trying to persist it, I get a 500 Internal Server Error.

create:1 POST http://127.0.0.1:8000/users/create 500 (Internal Server Error)

MyTaskController.php:

    /**
     * @Route("/tasks", name="task_list")
     */
    public function listTasks(TaskRepository $taskRepository): Response
    {
        $tasks = $taskRepository->findAll();
        dump($tasks);

        return $this->render('task/list.html.twig', [
            'tasks' => $tasks,
        ]);
    }

    /**
     * @Route("/tasks/create", name="task_create")
     */
    public function createTask(Request $request): Response
    {
        $task = new Task();
        $task->setCreatedAt(new \DateTime());
        $task->setUpdatedAt(NULL);
        $form = $this->createForm(TaskType::class, $task);

        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $this->entityManager->persist($task); // Use the EntityManager to persist the task
            dd($task);
            $this->entityManager->flush(); // Use the EntityManager to flush changes

            return $this->redirectToRoute('task_list');
        }

        return $this->render('task/create.html.twig', [
            'form' => $form->createView(),
        ]);
    }

My routes.yaml

task_list:
    path: /tasks
    controller: App\Controller\TaskController::listTasks

task_create:
    path: /tasks/create
    controller: App\Controller\TaskController::createTask

My entities:

User Entity:

namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use App\Repository\UserRepository;
use Doctrine\DBAL\Types\Types;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity(repositoryClass: UserRepository::class)]
#[ApiResource]
class User
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 255, nullable: true)]
    private ?string $username = null;

    #[ORM\Column(length: 255, nullable: true)]
    private ?string $name = null;

    #[ORM\Column(length: 255, nullable: true)]
    private ?string $surname = null;

    #[ORM\Column(length: 255, nullable: true)]
    private ?string $email = null;

    #[ORM\Column(length: 255, nullable: true)]
    private ?string $password = null;

    #[ORM\Column(length: 100, nullable: true)]
    private ?string $role = null;

    #[ORM\Column(type: Types::DATETIME_MUTABLE, nullable: true)]
    private ?\DateTimeInterface $created_at = null;

    public function getId(): ?int
    {
        return $this->id;
    }

    public function setId(int $id): static
    {
        $this->id = $id;

        return $this;
    }

    public function getUsername(): ?string
    {
        return $this->username;
    }

    public function setUsername(?string $username): static
    {
        $this->username = $username;

        return $this;
    }

    public function getName(): ?string
    {
        return $this->name;
    }

    public function setName(?string $name): static
    {
        $this->name = $name;

        return $this;
    }

    public function getSurname(): ?string
    {
        return $this->surname;
    }

    public function setSurname(?string $surname): static
    {
        $this->surname = $surname;

        return $this;
    }

    public function getEmail(): ?string
    {
        return $this->email;
    }

    public function setEmail(?string $email): static
    {
        $this->email = $email;

        return $this;
    }

    public function getPassword(): ?string
    {
        return $this->password;
    }

    public function setPassword(?string $password): static
    {
        $this->password = $password;

        return $this;
    }

    public function getRole(): ?string
    {
        return $this->role;
    }

    public function setRole(?string $role): static
    {
        $this->role = $role;

        return $this;
    }

    public function getCreatedAt(): ?\DateTimeInterface
    {
        return $this->created_at;
    }

    public function setCreatedAt(?\DateTimeInterface $created_at): static
    {
        $this->created_at = $created_at;

        return $this;
    }
}

Task Entity:

namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use App\Repository\TaskRepository;
use Doctrine\DBAL\Types\Types;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity(repositoryClass: TaskRepository::class)]
#[ApiResource]
class Task
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 255)]
    private ?string $title = null;

    #[ORM\Column(type: Types::TEXT, nullable: true)]
    private ?string $description = null;

    #[ORM\Column(length: 100, nullable: true)]
    private ?string $status = null;

    #[ORM\Column(type: Types::DATETIME_MUTABLE, nullable: true)]
    private ?\DateTimeInterface $createdAt = null;

    #[ORM\Column(type: Types::DATETIME_MUTABLE, nullable: true)]
    private ?\DateTimeInterface $updatedAt = null;

    #[ORM\ManyToOne]
    #[ORM\JoinColumn(nullable: false)]
    private ?User $user = null;

    public function getId(): ?int
    {
        return $this->id;
    }

    public function setId(int $id): static
    {
        $this->id = $id;

        return $this;
    }

    public function getTitle(): ?string
    {
        return $this->title;
    }

    public function setTitle(string $title): static
    {
        $this->title = $title;

        return $this;
    }

    public function getDescription(): ?string
    {
        return $this->description;
    }

    public function setDescription(?string $description): static
    {
        $this->description = $description;

        return $this;
    }

    public function getStatus(): ?string
    {
        return $this->status;
    }

    public function setStatus(?string $status): static
    {
        $this->status = $status;

        return $this;
    }

    public function getCreatedAt(): ?\DateTimeInterface
    {
        return $this->createdAt;
    }

    public function setCreatedAt(?\DateTimeInterface $createdAt): static
    {
        $this->createdAt = $createdAt;

        return $this;
    }

    public function getUpdatedAt(): ?\DateTimeInterface
    {
        return $this->updatedAt;
    }

    public function setUpdatedAt(?\DateTimeInterface $updatedAt): static
    {
        $this->updatedAt = $updatedAt;

        return $this;
    }

    public function getUser(): ?User
    {
        return $this->user;
    }

    public function setUser(?User $user): static
    {
        $this->user = $user;

        return $this;
    }
}