As a writer, you are never “blocked.”
Here, let me say it again, with more markup tags:
***As a writer, you are never “blocked.”***
The fact that you’re not actually writing doesn’t mean that you’re not actually working. You’re also working when you’re thinking. Figure out what the problems are and _solve_ them. Solve them in a half-assed way if you have to; slap enough duct tape over the problem that you can proceed to the next step. Go back later and improve it in the editing process.
Or! Just put the whole thing aside. Just for now. Even in the worst, most frustrating situation, you’re not “blocked.” You just can’t make any progress on this one thing.
So write something else.