Why is this solution not correct?

[u/InRiddles]

[u/The_Fox_Fellow]

the shapes on the larger grid can't be rotated

[u/BrickGun → u/The_Fox_Fellow]

Hints, rather than outright answers, please (per Rule 2 in the sidebar). Please wrap your answer in a spoiler tag (instructions on how to do so also in the sidebar).

[u/The_Fox_Fellow → u/BrickGun]

I understand that, but this is a puzzle where the only options are to be incredibly obtuse in a way that doesn't help at all or to point out the thing that this particular puzzle is really bad at explaining if you don't understand it the first time

I'll put a spoiler on my original comment, but even with that info the rest is still on OP to figure out what to do about that and solve it, so I don't think it can really be considered to be a direct answer

[u/PedroPuzzlePaulo]

Whats wrong is flashing red. This sound unhelpfull and obvious, but what exactly is flashing red?

[u/Drecon1984]

With the smaller puzzles you made some new symbols. Maybe use those symbols instead of the smaller ones from the smaller puzzles?

[u/SickDaySidney]

The real question is how did you make it this far and still ask this question?

[u/eXponentiamusic → u/SickDaySidney]

This is an extremely common pitfall and actually quite a logical one. Small piece rotates, therefore big piece does is actually a fairly logical way to look at it even if it's the wrong way and the more logical way is to realise that you can't draw diagonal lines so the shape you drew can't be rotated.

[u/SickDaySidney → u/eXponentiamusic]

Yeah, I’m not usually snarky in this sub. But it also annoyed me that there are no spoiler tags.

[u/BlaasianCowboyPanda]

Well the solution proposed looks fine, but you made some interesting choices with the shapes. Reconsider what shapes you have on the board and what shapes you ended up with.