I think I've had this problem a couple of times (all of them with KF-operated flights). One time I called SAS IT, who claimed there are two passengers with same name on the flight, disabling the OLCI.

I didn't buy that, so I called Blue1 (a horrendously expensive number) instead: they said name has nothing to do with the problem, but instead the travel agent has not transmitted passengers' titles (MR/MS) with the booking, hence must present ID at the counter. That was nonsense, since the CI worked without problem, without need to scan the passport, with the airport check-in machine.

I did, however, complain to the travel agent afterwards, who replied that there was nothing wrong with the booking... and indeed, I had booked several Blue1 flights around the same time, at the same online TA, and none of the other ones had any check-in problems.

On the other hand, I've also got a general OLCI error message in the past, and only at the airport did it tun out that the flight was actually cancelled.