ForeignKey при makemigrations выпадает в ошибку e300,e307 (отношение с абстрактной или неустановленной моделью)

Всем добрый день, помогите, пожалуйста, с моделями в django. Пытаюсь из модели contract ссылаться на counterpaty через foreignKey.

Код модели:

from django.db import models
from django.urls import reverse
class Сounterparty(models.Model):
    id = models.BigAutoField(primary_key=True)
    name = models.CharField(max_length=200, null=True, blank=True)
    full_name = models.CharField(max_length=200, null=True, blank=True)
    inn = models.CharField(max_length=200, null=True, blank=True)
    kpp = models.CharField(max_length=200, null=True, blank=True)
    okpo = models.CharField(max_length=200, null=True, blank=True)
    ogrn = models.CharField(max_length=200, null=True, blank=True)
    okved = models.CharField(max_length=200, null=True, blank=True)
    group = models.CharField(max_length=200, null=True, blank=True)

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse('counterparty', kwargs={'counterparty_id': self.pk})


class Contract(models.Model):
    counterparty1 = models.ForeignKey('counterparty',on_delete=models.PROTECT)
    choices = (
        ('1', 'Договор купли-продажи'),
        ('2', 'Договор энергоснабжения')
    )
    type = models.CharField(max_length=100, choices=choices, null=True)
    date = models.DateField(auto_now=True, null=True)
    number = models.IntegerField(unique=True)
    start_date = models.DateField(null=True)
    end_date = models.DateField(null=True)
    acpoint = models.CharField(max_length=255, null=True)
    rate = models.CharField(max_length=255, null=True)
    mrate = models.CharField(max_length=255, null=True)
    main_voltage = models.CharField(max_length=255, null=True)
    calc_scheme = models.CharField(max_length=255, null=True)

    def __str__(self):
        return self.number

    def get_absolute_url(self):
        return reverse('counterparty', kwargs={'counterparty_id': self.pk})

Ошибка при введении в терминал команды makemigrations:

    ERRORS:
main.Contract.counterparty1: (fields.E300) Field defines a relation with model 'counterparty', which is either not installed, or is abstract.
main.Contract.counterparty1: (fields.E307) The field main.Contract.counterparty1 was declared with a lazy reference to 'main.counterparty', but app 'main' doesn't pro
vide model 'counterparty'.

Приложение зарегистрировано в installed_apps