In the Rank Tracker module, you have the option to decide what's the scope of the URL when our software looks for your site in the SERPs for a given keyword.
There are 3 available URL scopes. For example purposes, let's say that your site is JoesWidgets.com.
This URL scope will match any page or subdomain on your site that appears in the SERPs for a given keyword.
When our sites looks at SERPs for the keyword in question, it will report a ranking position if it finds the exact domain (JoesWidgets.com).
It will also report a ranking position if it finds a sub-page (i.e. JoesWidgets.com/purple-widget) or if it finds a sub-domain (i.e. Store.JoesWidgets.com) in the SERPs.
This URL scope will match only the exact URL that you've configured for tracking in that campaign.
So if you're tracking rankings for JoesWidgets.com, and the software doesn't find the root domain, but it DOES find JoesWidgets.com/purple-widget and/or Store.JoesWidgets.com, it will return a result of "Not Found" for the keyword.
If you're interested in running a campaign which tracks ONLY JoesWidgets.com/purple-widget, and you don't care whether the root domain, a sub-domain ranks, or any other pages rank, then this is exactly the URL scope that you should choose.
There are two main use cases for this URL scope.
The first is when you want to match the root domain only, and exclude any sub-domains from being pulled in. An example would be if you're tracking results for JoesWidgets.com, and want to exclude sub-domains such as Store.JoesWidgets.com from being picked up in the SERPs. Ranking positions would be reported for either the root domain or a sub-page such as JoesWidgets.com/purple-widget, but would NOT be matched or reported for Store.JoesWidgets.com. If neither the root domain nor any sub-pages rank, but Store.JoesWidgets.com does rank, the reported result for that keyword will be "Not Found".
The second use case for the domain.com/* URL scope is when you want to match only a specific sub-domain and any associated sub-pages. In that second case, you would configure the campaign URL as the sub-domain that you wanted to track (such as Store.JoesWidgets.com). Rankings would be then be matched and reported for Store.JoesWidgets.com or for sub-pages of that sub-domain, such as Store.JoesWidgets.com/Category/Sales. Any rankings for the root domain (JoesWidgets.com) or for any other sub-domains (e.g. Blog.JoesWidgets.com) would not be reported.
With any of these options, if the software finds more than one result from your page in the SERPs (i.e., your subdomain, your root domain, and one or more pages from your site are all ranking for the keyword), then it will report the result with the highest SERP rank.
To change your scope settings, see this article.