Page not found.
In Umbraco v9+ you can specify the id of a specific page you wish to be used as your 404 Not found page. This can simply be done by adding the correct JSON to the appsettings.json file.
Add the Id of the page you wish to use as the 404 page within the “ContentId” property.
One thing to also be aware of is, you can define multiple 404 pages. This can be useful when working within a multi-language website.
