Looking for a simple answer to figure out the classic version of the Ontological Argument:
In the late-18th-century Critique of Pure Reason, Immanuel Kant provided the standard rebuttal to the classic ontological argument: the mere concept of what God is does not entail his existence. While we may conceive of God as having the property of being all-powerful (say), existing is not a property of a thing at all. (More specifically, existence is not a perfection.) So the second premise is false. God's existence concerns whether our concept of God corresponds to anything real, and pure reason cannot tell us that (unless the concept of God is self-contradictory, in which case God cannot exist). We can show that the classic ontological argument fails by keeping the erroneous second premise and replacing the first one with: "Utopia is the most perfect ('the greatest') society conceivable." The parallel conclusion that Utopia (or "the greatest car," or whatever) must exist is clearly false. Only observation could determine that such things exist. (Kant, 1787, 592-603)
Would one agree with Kant? If not, what in his logical is an error?
Whether or not you agree with Kant's assessment of the ontological argument is something you need to decide on. For what it's worth, his response to the argument is generally regarded by philosophers as a good one. Unfortunately, there isn't a "simple" answer to be found to your question, but simple answers are rarely found in ...
The solution discusses the classic versions of the ontological argument.