301 Redirects can be read as soft 404 errors by Google

Over the past few years many have asked the question as to where to best redirect their pages during new content creation, website redesign or website migration. When changing URLs it is extremely important to redirect old pages to new URLs via 301 redirects. It’s not good to have multiple URLs and this also becomes cumbersome and reduces the user experience.

“What happens when I don’t have a corresponding page on my new site?”, you ask. Perhaps it is an old product where all the content has been removed, or maybe it is a service that has been discontinued or no longer offered. Those pages may have attracted a lot of search traffic and therefore hold a high authority and rank well. You could send the traffic to your homepage, but what is really going to work and without dropping too much in ranks and losing equity?
Google has been known to treat redirects as soft 404 errors even when you direct traffic to the homepage or other content that may not be relevant. Unfortunately as Google sees this traffic as an error it is then removed from its index. However this makes sense to a user that could be searching for your product in google and then they land on your homepage instead of the product specific page.
There is no way to out-smart Google here, it is important to follow a one to one mapping when migrating to a new CMS or changing your domain all together. If you want to try and maintain strong rankings you need to match the URL from the old to the new making sure they contain the same relevant content.

How do I handle a redirect when my URL changes?

Again, it is best to use a one to one mapping system for any URLs on the site making sure you are mapping to the equivalent URL on the new site.

If you absolutely can’t find content that matches on your new site exactly, it is to put a 404 error on the page. Some 404s on your website are normal over time. Just make sure the 404 page is relevant to the user.

Example of a constructive 404 error page.

If you’re too late to the party and you already migrated your site years ago, it’s best to go back in and properly redirect older URLs to the correct new ones on your site. If the URLs are old from your previous site and there is no location of them on the internet, it’s best to phase them out altogether.