This alarm is intended to alert you if your website has recently been flagged as a disavowed domain in third-party tools such as Remove’em.  Disavow is a feature offered by Google for webmasters to deny any authority coming from a specific domain using Google’s Search Console.

You should review review your outbound links to ensure you are not using heavy commercial anchor text, which would cause someone to disavow your site.  Additionally, if you receive notices from webmasters requesting that you remove links, you should comply so as to minimize the risk of being included on several disavow files.