Hello, LambdaSP,
Thank you for getting in touch with us.
1/ Fixed. Please clear the cache and try to add a product to the cart now.
2/ Please read this article – https://www.8theme.com/documentation/xstore/troubleshooting/how-to-speed-up-my-website/
If you have any additional questions or concerns, please do not hesitate to reach out to us. Our support team is always available to assist you.
Kind Regards,
8theme team