Look here the output when running the jar in the terminal:
(basically, it thows java.lang.ClassNotFoundException: com.sun.javafx.util.Utils)
arian@Arians-MacBook-Pro jar % java -jar Lizard_and_The_Magic_Doors.jar
Exception in thread "Thread-0" java.lang.NoClassDefFoundError: com/sun/javafx/util/Utils
at engine.Renderer.setPixel(Renderer.java:79)
at engine.Renderer.drawImage(Renderer.java:421)
at objects.Menu.render(Menu.java:75)
at game.GameManager.render(GameManager.java:87)
at engine.Engine.run(Engine.java:83)
at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: java.lang.ClassNotFoundException: com.sun.javafx.util.Utils
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
... 6 more