What triggers this issue?
This issue reports the URLs that redirect, and the destination URLs return one of the 4xx (Client Error) or 5xx (Client Error) HTTP status codes.
https://ahrefs.com/blog/seo-metrics (301 Moved Permanently)
https://blog.ahrefs.com/seo-metrics/ (404 Not found)
Why is it important?
Neither the search engine crawlers nor your website visitors will be able to access these URLs via the links on your website. Crawlers will be forced to abandon the request while people will most likely leave your website.
How to fix it?
Look at the HTTP status code for the redirect URLs that cause this issue.
For 5xx HTTP status codes, try to reproduce this server error in your browser. You should also check the error logs for your server.
If this is an ongoing problem and a lot of internal pages return the 5xx code, you need to check with your hosting provider or with your web developers. Your server may be overloaded or misconfigured.
One of the possible reasons for this issue in the Site Audit tool is the high crawling speed set in your project's settings. Some servers are not able to process a large number of requests at a given time. Try setting lower crawling speed in the crawl settings and run a project re-crawl.
You should also note that this can be a temporary issue, e.g. when the crawl took place during some maintenance on your website's server.
For 4xx status codes, click on the number of inlinks in the table to get the list of pages that link to the particular redirecting URL.
Replace the links to redirecting URLs on these pages with direct links to relevant live pages or remove these links.
Alternatively, you can set up redirects for 4xx URLs. However, this will create an unnecessary redirect chain. So we recommend using direct links where practically possible.