What should I do with "Lexical or Preprocessor Issue (Xcode): 'PixelFree/SMPixelFree.h' file not found"

[Dollagon]

I just have a very simple codes like:

      final pixelfree = Pixelfree();
      await pixelfree.createWithLic('assets/pixelfreeAuth.lic');

and this error shows up, what should I do with it?

BTW, I'm using Flutter 3.35.6 and pixelfree 2.4.17