My Apple Watch serial number is not accepted by Apple support

I am trying to get the Apple support for my watch, but when I enter the serial number it is not accepted. I have verified that it is correct both on my watch itself and on the supporting iPhone. I have tried various countries (I bought it in Malaysia, live in Turkey but come from Sweden), but all of them do not recognise the serial number. The watch is bought from a authorised Apple outlet, so it is not pirate in any way. It is registered with my apple ID. What can be the fault?