Thoses are exactly the kind of endgames I always mess up to discover with the computer analysis that's supposed to be completely winning. Exactly why I began to study endgames in the first place. 
I got this position against an opponent and messed up in time scramble. Looked at the computer analisis, saw the winning move and it seemed all clear to me. Obvious! Seemed that obvious and so winning that I tried playing it against the computer full strenght. I often do that to train endgames: I take a position I'm supposed to win easily and play it against the computer, so I could confirm - in infirm a lot of time - that I understand well. Usually it takes a lot of try before getting it. I don't know if it's a good technique to train, but I find it more engaging than just looking at the analisis. 
So yeah, this exact winning endgame, I draw it one time against a human and lost it four time against the computer - wich is perfectly normal. It's +5 for white, white to move. I get how to get a second passed pawn and eventually win an important tempo, but it seems afterward the king and knights are blocking everything and I can't make progress. 
I suppose at this point I might win this endgame against a humain, but I'm still wondering what I'm missing. It seems that the c4 square is the door to progress, but black seems to always be in time to shut the door. Anyway, I will get it at some point. 
https://lichess.org/analysis/8/8/3n1k1p/p1p1pP2/Pp2P3/1P2K2P/3N4/8_w_-_-_0_52?color=white