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Hi Nikos, It's important to remember that Keyword Difficulty scores are a Moz metric, not a Google metric - they are based on Moz' ability to judge how well other sites are competing for that term, and may not capture the entire competitive landscape (since nobody except Google knows everything that Google looks at). Based on your ability to rank well for some terms and not others, it doesn't seem likely to me that you are under any sort of penalty, so much as that Google just isn't ranking you for some terms. In addition to the Keyword Difficulty scores for each term, take a look at which sites rank for the term (you can do this in the SERP Analysis feature of the Keyword Difficulty tool. Ask youself: What kinds of sites rank for this term? For example, if you are an individual business, but all of the sites and pages that are ranking for that term are aggregators or lists of multiple sites, it may be that Google has determined that an individual business site is not a good fit for that query. Similarly, if your page is a blog post and no other blog posts appear in the SERP, Google may have decided that a blog post isn't what people are looking for when they search that term. What is the search intent of the query? Based on the other pages that rank, what is the question or task that Google has decided users are trying to answer or complete when they search this term? Does your page do a better example of helping answer that question or complete that task than the other pages that rank? What types of content are ranking? Do they all have rich snippets? Are there images, video, shopping or maps results? All of these will tell you more about the kind of content Google thinks will match this query. Is there a specific page or website that is ranking for that term that you think you could push out of the top 10? Look for areas of opportunity. For example, maybe there is a site with high authority, but the page that ranks has very low page authority and doesn't fit the query very well. Try to create a page that is better than that page, specifically. How closely is the phrase related to your niche? You can tell from the keywords you are successfully ranking for, which topic areas Google is associating with your site. If you have a whole site about chocolates, it will be harder to rank a page about asparagus, even if the difficulty score is lower. Also, don't forget to continue promoting your content to earn high-authority links to individual content pieces. Where it makes sense to do so, you may also want to link internally from some of your more popular and successful pages to some of the pages that are struggling. I hope that helps!