If according to theory the player who is behind should attack as soon as possible, then 7 Bd3 is wrong. Should be 7 Bb4 at least if theory is correct.

on the 11th move, white allows exchanges, this does not seem right if white is behind in material. A better move seems hard to find here but perhaps 11 Nxd5 N(4)xd5 12 Bc4 Kh8 and now 13 Ne5 looks like a better time to put the N there; at least we are attacking the K.

Again on the 13th move white is effectively exchanging material which cannot be right. White gives up R for B but he isolates the h pawns and grabs the f pawn. AN equal material transaction in my book and also not right in theory since white is behind in material.

Perhaps he had the right idea on the 13th move and grabbing the pawn on the 14th was the mistake. What if 14 Qg3 Nh5 15 Qh4 Nf6 16 Nf3 this looks like more of an attack since putting the Q on the open g file aligns it with the black K. If white can follow this up with Re5 he can either gain back a pawn and equalize or continue his attack.

White had four eager pieces just past the equator on 15.Nb5 but that move does not pan out. Euwe surely thought his knights would wreck more havoc than they actually did. White was unable to occupy the glaring hole on e6 until the very end when it no longer mattered. Once the Black queen gets in the White camp dealing convenience checks, it's all but over.