ValueError: Related model 'users.customuser' cannot be resolved

Can't figure out what to do to solve this problem. I am trying to create a custom user model but when i try to migrate it throws this error.

Here is managers.py:

from django.contrib.auth.base_user import BaseUserManager
from django.utils.translation import gettext_lazy as _

class CustomUserManager(BaseUserManager):
    """
    Custom user model manager where email is the unique identifiers
    for authentication instead of usernames.
    """
    def create_user(self, email, password, **extra_fields):
        """
        Create and save a User with the given email and password.
        """
        if not email:
            raise ValueError(_('The Email or Phone numvber must be set'))
        email = self.normalize_email(email)
        user = self.model(email=email, **extra_fields)
        user.set_password(password)
        user.save()
        return user

    def create_superuser(self, email, password, **extra_fields):
        """
        Create and save a SuperUser with the given email and password.
        """
        extra_fields.setdefault('is_staff', True)
        extra_fields.setdefault('is_superuser', True)
        extra_fields.setdefault('is_active', True)

        if extra_fields.get('is_staff') is not True:
            raise ValueError(_('Superuser must have is_staff=True.'))
        if extra_fields.get('is_superuser') is not True:
            raise ValueError(_('Superuser must have is_superuser=True.'))
        return self.create_user(email, password, **extra_fields)

Here is models.py:

from django.contrib.auth.models import AbstractBaseUser, PermissionsMixin
from django.db import models
from django.utils import timezone
from django.utils.translation import gettext_lazy as _

from .managers import CustomUserManager


class CustomUser(AbstractBaseUser, PermissionsMixin):
    email = models.CharField(_('email or phone number'), max_length=175, unique=True)
    is_staff = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    date_joined = models.DateTimeField(default=timezone.now)

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = []

    objects = CustomUserManager()

    def __str__(self):
        return self.email

Thanks in advance, please explain what went wrong

Try this steps

settings.py

AUTH_USER_MODEL = 'your_app_name.CustomUser'

Steps

--- Delete `migrations` folder
--- also delete `db.sqlite3` (database file)
--- run command `python manage.py makemigrations your_app_name`
--- then run `python manage.py migrate`