Fitch's argument. Where I have gone wrong?

Any metaphysical modal wizards out there that can help me? Here's a line of reasoning that I think is true:
1. In order to wonder whether p is the case, one must be able, at least partially, to understand the content of p.
2. To understand the content of p is to able, at least in some cases, to know that p when it is clearly evident that p.

3. If one didn't know that p when p was clearly evident, then one would not understand that p.

4. Therefore if S understands the content of p, it must be possible for it to be clearly evident that p.
5. If S wonders whether or not "p" where p is a proposition expressible by a declarative sentence, then it must be possible to for S to know that p.
6. If S wonders whether or not p, then (at least in some cases) it is possible that p is true and it is possible that p is false.
7. Therefore it is possible to know a proposition that is false.

Conclusion: Knowledge is not necessarily factive.

Applications

It is possible to know that (p and nobody knows that p).
There are many instances of contingently necessary propositions, for example
Jack doesn't know that (there is extra terrestial plant life and Jack doesn't know that there is extra terrestial plant life).

I'm not interested in hearing people disagreeing with the conclusion, I expect that most people do. But it is possible that most people are wrong. What I want to know is which bit of the argument is wrong. I expect there is a scope fallacy going on, or perhaps an illicit blurring of epistemic and metaphysical necessity.