Most organic search from US - cannot take international orders

The company I work for is a brand operating ecommerce channels for each region. You cannot order from a region outside of your own.

I’ve found that most of our organic traffic is coming from the US and is hurting our conversion as they cannot purchase on our site, as they are then directed to the US platform.

What is the cause of this? Bad SEO from our end or the US site? I find it odd that we are ranking better than the US.