Just now, I got the donation form, so it might have been a short-term server problem.
Otherwise, there's a rather slim chance deleting cookies and clearing the browser cache _might_ help. Trying incognito/private mode would be a fairly decent way to test whether that would help.
If the problem persists and the cookies and cache thing does not help, please send feedback on the main web page. State that you already tried clearing the cache and deleting cookies, because that's often the first response to a report of a website problem.