Diagnose of broken Links

[RosaJBrassell]

You can use some tools to check broken links of your site such as  W3C Link Checker. It help you check if backlinks have broken or not, then you can remove them from pointing to your site.

[zanuda]

http://www.seomastering.com/seo-forum/seo_services__seo_tools/broken_links-39475/msg119299/#msg119299

[santhoshsocial]

Diagnose broken links  with these free tools:
1 – Xenu's Link Sleuth
2 – Google Webmaster Tools (GWT)
3 – Screaming Frog

[pablito]

Run Screaming Frog or Xenu's Link Sleuth to crawl your site and surface every 404, then cross-check Google Search Console's Coverage report for crawl errors. Fix dead internal links, 301-redirect moved URLs, and re-crawl. Do it monthly, because link rot never sleeps.