Ranking issue, need your explanations !

Hey BHW community,

first, sorry for my bad english it's not my native language.

I need some explanations because i have an issue about my serp.

I have a website created an June 2016. I've done link building for one keyword and backlink are redirect to my homepage. Homepage are optimized for this keyword.

But the issue, homepage are not ranked, instead of an internal page are ranked (position 7 at this time).

Why this inner page are ranked and not the homepage ? This homepage are not deindexed when i type site:mysite.com homepage appear.

(In the past, homepage was ranked in the first page, and now homepage disappear, and an internal page replace it)

Strange no ? I need to add more backlink and more social signal or ?

Thanks for your help.

.... Inner pages has got more content which brings much relevancy . I'm sure you have related KW in the page ranking currently .

I'll check thanks for your answer.