Broken Links
Broken links are URLs that lead to a page on your website that does not exist. Broken links are very common and are not an indication that there is anything wrong with your site.
Some common reasons for broken links:
You removed a product from your store
You moved a product to a new collection
You removed a collection from your store
You renamed a collection
You changed your primary domain
Redirects
Redirects allow that broken link to automatically be redirected to an existing page. This results in a better experience for your customers and allows you to continue to gain value from pages that have gained a lot of SEO value but no longer exist.
Plug in SEO monitors your site to discover broken links and create redirects.
Learn More: How Do I Set Up My Broken Links and Redirects?