SERP drop

I have a weird problem. I have this 1 site that was doing fantastically, that has all of a sudden started to really struggle to maintain its rank. Everyday it seems to drop by 2-3 placings.

See this image which should show what I am talking about


Note: I run around 30 money sites, and I don't normally struggle with rankings - Most of my sites are on page 1 or 2 for my main keywords and have been that way for months to years.

I want to know if anyone has any ideas on what is causing this type of SERP movement? The reason I am concerned is because I have used the same formula with lots of different sites, but this is the only one that is tanking. I'm honestly not sure what is going on.

Any thoughts/suggestions would be appreciated - thanks.

It's pretty hard to tell you what is causing it from a graph and knowledge that you have 30 good money sites.

I experienced this kind of issue once.. I slowed down on the number of backlinks each day but never stopped I will take few weeks before you could see the site jumped back to a higher position than it ever was. keep on building links steadily

The average position while ranked was continuing to improve, until around the 6th January. If the position continued to improve thereafter, I would have looked to try to tie those big cliff-drops to the days after link building activity, and call it a bounce.

However, given that the ranking on average appears to be declining now, the first thing that comes to mind is that somewhere around late December or early January, you picked up some toxic links. I'd look closely at new links from around that period, perhaps.

Perhaps your content are less quality and you fail to acquire quality backlinks.Could you let us know about the quality of those two factors,please