Got AttributeError when attempting to get a value for field `email` on serializer `UserSerializer` - serialization

Question

Creating Django REST FRamework API. Using Abstract User and email is the default logging parameter using.
AttributeError at /post/
Got AttributeError when attempting to get a value for field email on serializer UserSerializer.
The serializer field might be named incorrectly and not match any attribute or key on the Post instance.
Original exception text was: 'Post' object has no attribute 'email'.
class PostSerializer(ModelSerializer):
category = ReadOnlyField(source='category.name')
author = UserSerializer(source='user.email')
#question = serializers.CharField(source='question.text', read_only=True)
class Meta:
model = Post
fields = '__all__'
class User(AbstractUser):
username = models.CharField("Username", max_length=50, unique=True)
email = models.EmailField("Email Address", max_length=254, unique=True)
USERNAME_FIELD = 'email'
REQUIRED_FIELDS = ['username', 'first_name', 'last_name']
class Post(models.Model):
STATUS_CHOICES = (
('draft', 'Draft'),
('published', 'Published'),
)
title = models.CharField(max_length=250)
slug = models.SlugField(max_length=250, unique_for_date='publish')
author = models.ForeignKey(User, related_name='posts', on_delete=models.CASCADE, to_field='email')
category = models.ForeignKey(Category, related_name='categorys', on_delete=models.CASCADE)
body = models.TextField()
image = models.ImageField(upload_to='blog/%Y/%m/%d', blank=True)
publish = models.DateTimeField(default=timezone.now)
rating = models.IntegerField("Rumor Rate", validators=[MaxValueValidator(5), MinValueValidator(0)], default=1, null=True)
created = models.DateTime[![enter image description here][1]][1]Field(auto_now_add=True)
updated = models.DateTimeField(auto_now=True)
status = models.CharField(max_length=10, choices=STATUS_CHOICES, default='draft')

Answer 1

I suppose you want to return the author's email in the author field when you request the Post endpoint. You may also convert the author field in the serializer to a ReadOnlyField (as category) and specify source='author.email', since your model foreign key is named like that:
class PostSerializer(ModelSerializer):
category = ReadOnlyField(source='category.name')
author = ReadOnlyField(source='author.email')
# ...