OLCI for NH flight has restrictions.
https://www.ana.co.jp/wws/japan/e/as...nline-checkin/
#(8) below may be applicable to your case.
Online Check-in is not available in the following cases.
(8) If you are a passenger who booked/purchased an ANA Group operated international flight under a different airline's flight number. (Your ticket number is required.) *1
*1 Online Check-in is available but, the auto check-in function will not be provided.
* Online Check-in may be unavailable due to system related issues or other reasons. Please check-in at the airport.
I'm not sure how and where to put in the ticket number when OLCI.