Hello @Stelio,
It appears that you have created the Cart page using the Elementor page builder and have set a custom max-width, which is causing the issue on your site. Please refer to the screenshots provided at the following links: https://postimg.cc/2LvxJkRW & https://postimg.cc/LqbB8Ymf
To resolve the issue, you will need to find and remove the max width by editing the column of the Elementor on that page.
Alternatively, if you would like us to investigate further, please provide your site’s WP Admin URL and credentials in the private content area of this topic.
Best Regards,
8Theme’s Team