Hi,

If your Odoo website suddenly shows "Page Not Found," start by checking if the website is still published within the Odoo Website app. Verify that you're using the correct URL, either through the Odoo admin interface or by checking your custom domain settings. Clear your browser's cache and cookies, or try a different browser to rule out local issues.

If you have access, check the Odoo server logs for errors. For Odoo Online users, check the system status page for outages. If these steps don't resolve the issue, contact Odoo support, providing your database URL and website name. It's unlikely you've lost your data; the problem is likely related to the website's publication status or URL configuration.

Hope it helps

Please contact Odoo Support at odoo.com/help