LDAP sync fails on first login afer configuring LDAP

On first login after configuring LDAP authentication, LDAP sync for the person fails:

  File "/usr/local/lib/python3.9/dist-packages/aleksis/apps/ldap/util/ldap_sync.py", line 206, in ldap_sync_user_on_login
    person = ldap_sync_from_user(user, ldap_user.dn, ldap_user.attrs.data)
  File "/usr/lib/python3.9/contextlib.py", line 79, in inner
    return func(*args, **kwds)
  File "/usr/local/lib/python3.9/dist-packages/aleksis/apps/ldap/util/ldap_sync.py", line 263, in ldap_sync_from_user
    raise KeyError(f"No matching fields found for {dn}")

Firstly, LDAP synchronisaiton should not be enabled by default. Secondly, it should fail gracefully, and tell what is going wrong.