Python requests login results in error 404

I'm trying to login to this website using python. To login, the following parameters are required:

Content-Disposition: form-data; name="__RequestVerificationToken"
Content-Disposition: form-data; name="Username"
Content-Disposition: form-data; name="Password"
Content-Disposition: form-data; name="ufprt"

__RequestVerificationToken and ufprt can be obtained by making a get request to https://treat.com/SignIn 
Username and Password are the login details

I'm triying the following code to get the request parameters

url = "https://treat.com/SignIn"
s = requests.Session()
response2 = s.get(url)
request_verification_token = BeautifulSoup(response2.text, 'html.parser').find('input', {'name': '__RequestVerificationToken'})['value']
ufprt = BeautifulSoup(response2.text, 'html.parser').find('input', {'name': 'ufprt'})['value']

I also store the cookie returned in the response

cookie = response2.cookies.get('__RequestVerificationToken')

Then the post request is built:

payload = {'__RequestVerificationToken': (None, request_verification_token),
           'Username': (None, '<my_user>'),
           'Password': (None, '<my_pass>'),
           'ufprt': (None, ufprt)}

headers = {
    'Cookie': cookie,
    'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36',
    'Accept': '*/*',
    'Accept-Encoding': 'gzip, deflate, br',
    'Connection': 'keep-alive',

}

response3 = s.post(url, headers=headers, files=payload)

Request does not look bad

but I'm always getting an error 404 as shown