Custom User Register Problem (NOT NULL constraint failed: mainaccount_myuser.password)

I changed the user model for a custom user model. Drop all migrations and deleted db.sqlite3 files. The model was working fine. I can register users through the admin page, but when i go to from creating the user, to change my user and finishing the registration process, this error pops up: (NOT NULL constraint failed: mainaccount_myuser.password)

how can i finx this error?

admin.py:

from django import forms
from django.contrib import admin
from django.contrib.auth.models import Group
from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
from django.contrib.auth.forms import ReadOnlyPasswordHashField
from django.core.exceptions import ValidationError
from django.contrib.auth import get_user_model


MyUser = get_user_model()
class UserCreationForm(forms.ModelForm):

    password1 = forms.CharField(label='Password', widget=forms.PasswordInput)
    password2 = forms.CharField(label='Password confirmation', widget=forms.PasswordInput)

class Meta:
    model = MyUser
    fields = ('email', 'date_of_birth', 'full_name')

def clean_password2(self):
    # Check that the two password entries match
    password1 = self.cleaned_data.get('password1')
    password2 = self.cleaned_data.get('password2')
    if password1 and password2 and password1 != password2:
        raise ValidationError("Passwords don't match")
    return password2

def save(self, commit=True):
    # Save the provided password in hashed format
    user = super(UserCreationForm, self).save(commit=False)
    user.set_password(self.cleaned_data['password1'])
    
    if commit:
        user.save()
    return user


class UserChangeForm(forms.ModelForm):
    
    password = ReadOnlyPasswordHashField()

    class Meta:
        model = MyUser
        fields = ('email', 'password', 'full_name', 'date_of_birth', 'is_active', 'is_admin') 


class UserAdmin(BaseUserAdmin):

    form = UserChangeForm
    add_form = UserCreationForm

    list_display = ('email', 'full_name', 'date_of_birth', 'is_admin')
    list_filter = ('is_admin', 'email', 'full_name', 'date_of_birth',)
    fieldsets = (
        (None, {'fields': ('email', 'password')}),
        ('Personal info', {'fields': ('date_of_birth', )}),
        ('Permissions', {'fields': ('is_admin',)}),
    )


    add_fieldsets = (
        (None, {
            'classes': ('wide',),
            'fields': ('email', 'date_of_birth', 'full_name', 'password1', 'password2'),
        }),
    )
    search_fields = ('email', 'full_name',)
    ordering = ('full_name','email', 'date_of_birth', 'is_admin',)
    filter_horizontal = ()



admin.site.register(MyUser, UserAdmin)

admin.site.unregister(Group)



model.py
from django.db import models
from django.contrib.auth.models import (
BaseUserManager, AbstractBaseUser
)


class MyUserManager(BaseUserManager):
    def create_user(self, email, date_of_birth, full_name, password=None):
    
        if not email:
            raise ValueError('Users must have an email address')
        if not date_of_birth:
            raise ValueError('Users must have an date_of_birth')
        if not full_name:
            raise ValueError('Users must have an full_name')
    

        user = self.model(
            email=self.normalize_email(email),
            date_of_birth=date_of_birth,
            full_name = full_name,
        )

        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, email, date_of_birth, full_name, password=None):

        user = self.create_user(
            email,
            password=password,
            date_of_birth=date_of_birth,
            full_name=full_name,
        )
        user.is_admin = True
        user.save(using=self._db)
        return user


class MyUser(AbstractBaseUser):
    email = models.EmailField(
        verbose_name='email address',
        max_length=255,
        unique=True,
    )

    full_name =models.CharField(
        max_length=255,
        )
    date_of_birth = models.DateField()
    is_active = models.BooleanField(default=True)
    is_admin = models.BooleanField(default=False)

    objects = MyUserManager()

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['date_of_birth', 'full_name']

    def __str__(self):
        return self.email

    def get_full_name(self):
        return self.full_name

    def get_short_name(self):
        return self.email

    def has_perm(self, perm, obj=None):        
        return True

    def has_module_perms(self, app_label):
        return True

    @property
    def is_staff(self):
        return self.is_admin