Users aren’t sending us feedback rating

we just launched a beta version of a website, where we included a feedback rating system.

A question, five stars and a comment box.

However, in three weeks, we had 0 feedback. Analytics show people are using the beta version.

This is how the feedback looks:

Note: Some inhouse people said they haven't noticed the question because of the colour. I agree, there's a possibility they really haven't, but that couldn't be the case for hundreds of monthly users, right? Also, the rating is sticky and follows the user.

I'm positively sure there's a stronger reason for the lack of ratings.

My personal theory is that users think they only need to click "send" when they enter a comment, but not for the rating part. Because we are used not confirming this kind of ratings.

What do you all think could be the reason and a feasible solution?