Use configured Site name instead of request host Django (Rest) Auth

account_adapter.py

from allauth.account.adapter import DefaultAccountAdapter
from django.contrib.sites.shortcuts import get_current_site
from django.contrib.sites.models import Site

class AccountAdapter(DefaultAccountAdapter):

    def get_email_confirmation_url(self, request, emailconfirmation):
        """ Override to get domain name from Sites configuration instead of request """
        # when 'request' is empty, the url from Sites is used
        try:
            # test if sites framework is configured
            if get_current_site(None):
                return super().get_email_confirmation_url(None, emailconfirmation)
        except Site.DoesNotExist:
            pass
        return super().get_email_confirmation_redirect_url(request, emailconfirmation)

settings.py

INSTALLED_APPS = [
    # installed apps
    'django.contrib.sites',             # required for allauth
    # more apps
]

ACCOUNT_ADAPTER = 'my.site.account_adapter.AccountAdapter' # override Allauth adapter