Hi @nouhefikri
This issue is usually due to cross-domain restrictions which are imposed for security reasons.
Unfortunately, WooCommerce and WordPress are not designed to work across different domains in this way. The sessions are not shared across different domains, hence the cart appears empty.
A better approach might be to use the WooCommerce REST API to create a custom checkout experience on your other domain. This way, you can ensure cart data is correctly handled without circumventing browser security measures.
Remember this can be a complex task requiring knowledge of coding, APIs, and WordPress, so you may need a developer to assist.
A more simple solution would be to link directly to the product or checkout page on the original domain. This way, users will be redirected to your WooCommerce store when they want to make a purchase.
I hope this information helps.