Authentication error using OAuth with exchangelib

Question

I am working on a Python based client code to access Microsoft Outlook 365 emails via OAuth2 and get all emails. But when I try to connect with my OAuth credentials, I get an UnauthorizedError.

creds = OAuth2Credentials(
    client_id=CLIENT_ID,
    client_secret=CLIENT_SECRET,
    tenant_id=TENANT_ID,
    identity=Identity(primary_smtp_address='x@y'),
)
cfg = Configuration(
    server='outlook.office365.com',
    credentials=creds,
    auth_type=OAUTH2,
)

#FIXME Following line attempts to create a session with EWS. Currently failing
account = Account(
    primary_smtp_address='x@y',
    config=cfg,
    autodiscover=False,
    access_type=DELEGATE,
)