A 404 error is a standard response that indicates:
-
A server is down.
-
It cannot find the requested content (due to file or domain removal).
-
The requested URL is broken.
Set one of your pages as a 404 page so that when a visitor tries to visit a page with the mentioned issues above, they will be redirected to your 404 page.
-
Open the campaign.
-
Click "Page Actions."
-
Select "Make This My 404 (Error) Page."
-
Publish the page.