Online booking system/flight search
 

I'm having problems looking at multi-city flights, in this case OSL-SIN-AKL-OSL out November and return January. I can search OSL-AKL-OSL and it produces flights and fares with no problem but with multi-city search adding a stopover in SIN I get the following error:

"We cannot process your request right now. Please try again later, or get in touch with your local Singapore Airlines office."

I guess the only way to book the stopover flight would be via the sales office because if booking the straightforward return then trying to change to include a stopover in SIN there is a hefty charge to change the SIN-AKL sector to a later date.