exchangelib can't access inbox messages

Question

I'm trying to use exchangelib to access my exchange account and automate some tasks. I can use my credentials to log in and send messages but I can't print inbox list. The code I'm trying to run is:

from exchangelib import Credentials, Account, DELEGATE
class ExchangeConnecter:

    def __init__(self, credentials: Credentials, email: str) -> None:
        self.credentials = credentials
        self.email = email
        try:
            self.account = Account(
                primary_smtp_address=self.email,
                credentials=self.credentials,
                autodiscover=True,
                access_type=DELEGATE,
            )
        except:
            fatal_error = sys.exc_info()[0]
            print(f"error: {fatal_error}")

    def get_list(self):
        email_list = self.account.inbox.all()
        return email_list

#use your own exchange credentials to reproduce the issue
mail = "[email protected]"
domain = "DOMAIN\\johndoe"
password = "somepassword"
credentials = Credentials(domain, password)

connecter = ExchangeConnecter(mail, credentials)
list = connecter.get_list()
print(type(list)) #None!?

When I try to use the returned object I get a TypeError: NoneType. I tried to check the documentation but I don't seem to find a mistake in this particular snippet of code.