When you’ve made a list of all the mistakes, try to explain why they occurred on such particular sites. They may be the product of an action taken by another team or the result of an SEO approach that was not well prepared. Wherever the mistake comes from, you’re going to have to find a way to correct it, here are few tips.
Implement a custom 404 page with a corporate image and some links back to the key categories or homepage: this way, you’ll avoid your guests visiting your website.
Generally, you don’t want users to experience a 404, so consider submitting links to sites that do exist!
Assign a 301 redirect to the 302 if it is not to be deemed temporary.
Add a 410 to the sites that Google isn’t meant to find, but look out! It’s a big action. Most of them would be orphaned sites, but make sure they don’t get any related connections.
There are not many things SEO Professional can do when it comes to server bugs, so get in touch with the developers to fix them.
Using the SEO Crawler to easily detect site errors and minimize the effect on SERPs. All webmaster must recognize all status codes, so the use of a very detailed tool helps even the least skilled website owner.