Hello,
I can check that you are using a custom base for your products:

The Remove Base option only works with the default product base. Please switch to the default base and enable the Remove Base option. It should work fine after that.
Let us know how that goes. Looking forward to helping you.
I switched to default and activated Remove Base,bit 494 error persists. Can you try yourself?
Hello,
We apologize for the delay in response.
I went ahead and troubleshoot your website and it seems that the plugin “Permalink Manager Lite” is causing the issue here. The mentioned plugin is forcing the product permalink to return /상품/ instead of the default /product/ resulting in a 404 page.
Kindly ensure that the setting in the “Permalink Manager Lite” plugin is configured correctly to avoid conflict with Rank Math or you may check this with their support team.
Thank you.
Hello,
Since we did not hear back from you for 15 days, we are assuming that you found the solution. We are closing this support ticket.
If you still need assistance or any other help, please feel free to open a new support ticket, and we will be more than happy to assist.
Thank you.