Superuser permissions

I have a very simple model:

from django.db import models
from djangoldp.models import Model

class Tube(Model):
    title = models.CharField(max_length=50)
    author = models.CharField(max_length=50)
    tubeid = models.CharField(max_length=50)

    def __str__(self):
        return self.title

I'm logged in as a superuser. I'm trying to create a new resource:

POST http://localhost:8000/tubes/

{"title":"Survivor - Eye Of The Tiger (Official HD Video)","author":"","tubeid":"btPJPFnesV4","@context":{...}}

But I get a 403 error:

{
	"detail": "You do not have permission to perform this action.",
	"@context": "https://cdn.happy-dev.fr/owl/hdcontext.jsonld"
}

There is no permission activated on my model and I'm logged in as a superuser. Why would I get a permission error?