Hi guys, starting from January my main site started to drop some position on my main KW. I thought the drop of my rating was done by my forum. In the last days of December I made a forum and linked site and forum by each other. Anyway, today I made Lite membership to ahrefs... And I found a backlink I never saw before. First time seen by ahrefs: 13 Jan '16. Just when my site started to drop position. I tried to open that domain, but it's flagged as bad site by firefox and chrome. Anyway, the backlink doesn't come from that site directly. Backlink comes from a subdomains that doesn't have the flag. Also, the link on subdomains are no - follow. So, how should I view this subdomain? As a bad backlink or not? Keep in mind my main site just have 9 domain refferal so far, and this backlink is one of them.