Hi,
You have 7 variants and I assume that the combination in your second screenshot do not point to one of these 7 existing variants.
When a variant does not exist ; it is not possible to add it into the cart (because it does not exist) ; that's why it display that the product do not have any stock.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.