Board Game Arena

I was trying to form a federation, but no matter what combination I used, it would either be too few buildings or too many buildings. Like, the below combination was deemed "too many buildings" and I don't understand why. Thanks! image is here.

I believe the issue is that there's a shorter path to the bottom mine.

You have the tech tile that makes Planetary Institute and Academies worth 4 power, so you could form your federation with the 3 adjacent buildings, you didn't need the extra mine.