I'm trying to check-in online for my trip back home from Phuket (HKT-HKG-LHR-BGO on KA/CX/BA) tomorrow, but keep getting this error message:

"Service Unavailable - Zero size object
The server is temporarily unable to service your request. Please try again later."

I've tried several times since OLCI opened at T-48 (17 hours ago). I was op-upped from Y to PE on the LHR-HKG segment (as 1 of 7 pax on the PNR), could that be a possible culprit? I asked the CX agent at Heathrow if the reservation would be split to process the upgrade, but he said that it wouldn't be, and everything seems to be OK in Manage My Booking.

Any suggestions?