Whenever I try to, the analysis doesn't start and it just reloads the page.
You may have hit the daily limit (30, I think).
It got increased a while ago. And also it's more complicated than that. The gist of it is 160/week and 35/day, whichever you hit first. But to ensure you won't have zero analysis for multiple days because of the weekly limit, you only get 20/day if already used 100 (i.e. 2/3) this week.
That's assuming we are talking about server analysis here. If you have issues with your local analysis which you can use infinitely, the issue must be something else.
