I tried to change to https and it didnt work

I was in settings trying to change the address to https and i wasnt able to do so. I wound up with the existing 404 error on my homepage, and im unable to log in. I cant get pass the 404 to change anything. here is how my homepage login aka wp-admin looks. https://www.designsforwebct.com/404.html
any help is much appreciated.