Post 400 (bad Request)

I'm attempting to submit my form, but it continually fails as there's something wrong with the POST. I'm unsure where/what exactly is causing the server to not process the request

Solution 1:

Usually, bad request means that you're trying to fetch data from request object using invalid keys. So you need to make sure that your POST request body (that was sent by javascript) contains all keys which you're using as arguments of request.form.get() method: first_name, last_name, etc...