You've probably already noticed the current versions of iOS 11 (11.0, 11.0.1 and 11.0.2) are not always compatible with your DxO ONE. Your DxO ONE might not be recognized when you connect it.
This issue may resolve itself if you reconnect your DxO ONE several times. Moreover, this problem seems to have been permanently resolved in iOS 11.1.
Our technical support team is ready to answer any questions you might have at https://support.dxo.com/hc/en-us/requests/new.
We would like to apologize for this inconvenience, which unfortunately was out of our control. Thank you for your understanding and support.