Solvable studies that computers fail to crack Are there chess studies that require an outside of the box thinking that goes beyond the concrete calculation capabilities of today's engines (e.g. Stockfish)? 

I have sometimes seen certain endgames that are known to be fortresses (drawn) but since the engine have depth limitations they cannot see all the way through and keep assessing them as winning for one side (for example giving +2 evaluation). But are there examples, to which we know the forced solution (checkmating line), but still the engines fail to solve?
Here is an outrageous mate in 57 puzzle which none of the top 3 engines are able to solve:

[fen "8/6pp/5p2/k7/3p4/1Q2p3/3prpp1/3Kbqrb w - - 0 1"]

1.Qc4 Kb6 2.Qd5 h6 3.Qc4 Ka5 4.Qb3 h5 5.Qc4 Kb6 6.Qd5 h4 7.Qc4 Ka5 8.Qb3 h3
9.Qc4 Kb6 10.Qd5 h2 11.Qc4 Ka5 12.Qb3 g6 13.Qc4 Kb6 14.Qd5 g5 15.Qc4 Ka5
16.Qb3 f5 17.Qc4 Kb6 18.Qb4+ Kc6 19.Qa5 f4 20.Qe5 g4 21.Qf5 Kd6 22.Qb5 f3
23.Qf5 Kc6 24.Qg5 Kd6 25.Qb5 d3 26.Qf5 Kc6 27.Qa5 Kd6 28.Qb5 Kc7 29.Qa6 Kb8
30.Qb6+ Ka8 31.Qc7 g3 32.Qc8+ Ka7 33.Qc6 Kb8 34.Qa6 Kc7 35.Qb5 Kc8 36.Qb6 Kd7
37.Qc5 Kd8 38.Qc6 Ke7 39.Qd5 Ke8 40.Qd6 Kf7 41.Qe5 Kf8 42.Qe6 Kg7 43.Qf5 Kh8
44.Qg5 Kh7 45.Qe5 Kg8 46.Qf6 Kh7 47.Qf8 Kg6 48.Qe7 Kh6 49.Qf7 Kg5 50.Qe6 Kh5
51.Qe8+ Kg4 52.Qf8 Kg5 53.Qf7 Kg4 54.Qf6 Kh5 55.Qg7 Kh4 56.Qg6 Kh3 57.Qh5#


Aside from the fact that the mating line is an absolute unit, an important reason why engines are unable to solve this is due to a technique called "Null move pruning".

Null move pruning assumes that playing no move is always worse than playing a move, which allows chess engines to search deeper by using this assumption to prune moves which are probably bad. However, because of this assumption, null move pruning is tactically vulnerable in zugzwang positions. 

In the above position, black is pretty much perpetually in zugzwang, so null move pruning prevents most programs from being able to see how black's king is forced around the board. As a result, Houdini, Stockfish and Komodo all report draws.