I can’t be sure without seeing your site (you have it locked down with a coming soon page) but I suspect a third-party plugin is adding some code after the footer or in the WP footer.
I would recommend temporarily deactivating all your current active plugins, with the exception of the main WooCommerce plugin. Then see if the problem is fixed.
If the problem has gone away, then re-activate your plugins one-by-one until the problem reappears.
This will show you which plugin, if any, is causing this issue.
If you do this and the problem is still there even with all plugins deactivated, please let me know.