To filter for lost backlinks due to "Broken redirect", you can use Site Explorer > Backlinks > Lost, and filter for Status: Broken redirect:
Every once in a while, you might stumble upon a lost backlink marked as "broken redirect". But when you check the link, the redirect chain still works. There can be several reasons as to why it can happen. Here are the most frequent ones:
4XX or 5XX status codes. At the time our crawler was checking the links within the redirect chain, there was a technical issue, and, at least, one of the URLs returned one of the 4XX or 5XX status codes. Which means that the page wasn't accessible and our bot failed to verify the redirect.
Ahrefs Crawler is Blocked. Since some sites might block, or partially deny access to our crawler. If the backlink is via a redirect chain, one of the URLs within the redirect chain can deny access for our crawler.
(URL) does not redirect anymore. If our bot finds that the redirecting URL no longer redirects, we will consider this redirect broken.
URL dropped. We drop some pages from our index from time to time to keep our index fresh and of good quality. If any one of the URLs within a redirect chain backlinking to the target website is dropped, we will record that backlink as lost. Read more about Dropped links.
You can open each of the pages within the redirect one by one in Site Explorer with exact URL mode to see the response that we get when the URL was crawled:
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