I'm trying to check-in my mother who is flying ex-EU to the USA, with LH operating the intra-Europe segment to CPH.

At H-30, she still can't check-in on the SAS appli. I tried to check in on the LH website to no avail- her booking réference and personal data pull up correctly but then I get a validation error when I click to proceed further with check-in.

Any ideas on how to proceed ?