How to customise error pages
Specific error pages
Zotonic’s controller_http_error first tries to find an error page
template that is specific for the HTTP status code, named
templates/error.status_code.tpl. So, to override the 404 template,
create a file templates/error.404.tpl.
Generic error page
If no specific error page template exists, Zotonic falls back to the generic
templates/error.tpl.