Hi Salva, thank you for your suggestion, it is indeed due to certain plugin conflict.
However, I am currently facing another problem, I have added region, stocks, and warehouse location for a certain product.
But when I click add to cart, it says "Sorry, this product is unavailable. Please choose a different combination." without asking which postal/area am I at, could you kindly advise?
Thanks!
Regards,
Ying Xuan