I have implemented auth in my django app using django-rest-auth. My settings in settings.py:
ALLOWED_HOSTS = []
# Application definition
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'rest_framework',
    'rest_framework.authtoken',
    'rest_auth',
    'django.contrib.sites',
    'allauth',
    'allauth.account',
    'rest_auth.registration',
    'corsheaders',
    'rest_framework_docs',
    'tasks'
]
MIDDLEWARE = [
    'corsheaders.middleware.CorsMiddleware',
    '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 = 'urls'
CORS_ORIGIN_ALLOW_ALL = True
CORS_ALLOW_CREDENTIALS = True
ALLOWED_HOSTS = ['*']
SITE_ID = 1
I am logged in from my frontend- I receieved a token with I have stored in my local storage. Now I making a simple GET request like following:
  getTasks(): Observable<Task[]> {
    let headers = new Headers({ 'Access-Control-Allow-Origin': '*' });
    let options = new RequestOptions({ headers: headers, withCredentials: true  });
    return this.http.get(this.taskUrl, options)
    .map(this.extractData)
    .catch(this.handleError);
  }
But it gives me : Request header field Access-Control-Allow-Origin is not allowed by Access-Control-Allow-Headers in preflight response. although I am including withCredentials. 
What am I doing wrong?
P.S: If I remove options from POST then there is no error but I get incorrect data because my backend returns data for a specific user.
Remove this line,
let headers = new Headers({ 'Access-Control-Allow-Origin': '*' });
from your getTasks() function. You don't need to specify those options to the server. django-cors-headers takes care of that.
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