You should be able to fill the form as it is a Google Form that is integrated into the webpage. Perhaps, something on the browser level is the issue here. I suggest that you clear cookies and re-try with filling the form. I also suggest that you use another browser as well as an Incognito window. This will isolate the browsers.
Ad-blockers as well as blocked cookies and blocked Javascript can cause these issues. The form is working as I have attempted to fill it out a few times across a few browsers and I had no issues with it.