You're accessing the development server over HTTPS, but it only supports HTTP. code 400, message Bad request syntax

I just started learning Django framework, and I tried to deploy my first project on the server from DigitalOcean. If I run

python3 manage.py runserver 0.0.0.0:8000

The server launches. However, once I try to access it from (my-rent-ip):8000 I get this:

[25/Aug/2021 01:49:01] code 400, message Bad request syntax ('\x16\x03\x01\x02\x00\x01\x00\x01ü\x03\x03GÛî}ز\x921\x0e\x94\x17\x9cÏe¹\x88ñÿÃ\x16\x01éÖRÝ\x00\x95F\x8aG\tÉ 8¯,úÂ\x93´ù\x06Ý\x14¾z\x13Âe4[\x9a,.æ\x96+$<~\x8eq<´\t\x00"ZZ\x13\x01\x13\x02\x13\x03À+À/À,À0̨̩À\x13À\x14\x00\x9c\x00\x9d\x00/\x005\x00')

[25/Aug/2021 01:49:01] You're accessing the development server over HTTPS, but it only supports HTTP

How is this possible if I run production server, not a development one?

I might be doing something wrong with the setting.py since it had to be changed a lot for the production purposes. I made a production branch, changed settings.py file, and cloned to the server using GitHub. Here it is:

from pathlib import Path

from dotenv import load_dotenv   #for python-dotenv method
load_dotenv()

# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent


# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/3.2/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
import os 

SECRET_KEY = os.environ.get('SECRET_KEY')

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = False
# DEBUG = os.environ.get('DJANGO_DEBUG', '') != 'False'


ALLOWED_HOSTS = ['*']


# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'pages',
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'mysite.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'mysite.wsgi.application'


SECURE_SSL_REDIRECT = True
SESSION_COOKIE_SECURE = True
CSRF_COOKIE_SECURE = True


# Database
# https://docs.djangoproject.com/en/3.2/ref/settings/#databases

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': BASE_DIR / 'db.sqlite3',
    }
}


# Password validation
# https://docs.djangoproject.com/en/3.2/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]


# Internationalization
# https://docs.djangoproject.com/en/3.2/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_L10N = True

USE_TZ = True


# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/3.2/howto/static-files/

STATIC_URL = '/static/'

STATICFILES_DIRS = [
    BASE_DIR / "static",
    '/var/www/static/',
]

# Default primary key field type
# https://docs.djangoproject.com/en/3.2/ref/settings/#default-auto-field

DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

Thank you so much!

Your server does not support https, so set these settings:

SECURE_SSL_REDIRECT=False
SESSION_COOKIE_SECURE=False
CSRF_COOKIE_SECURE=False

Probably now you need to clear the caches of your browser and restart your server. The error message refers to the development server because python3 manage.py runserver is used only in development. Note that you should set up https in your production server (when you will have set up https sets again settings that we changed earlier to True) and that setting ALLOWED_HOSTS = ['*'] is a security issue.