Like you i had also facing same problem ,here is my problem.
1). when i update my domain name in prestashop 1.7 and enable friendly url from back office.
it will show me 404 error.But with out enable its working fine.
So friends don't worry about the problem i have a permanent solution of that Now my shop working fine.
when we update our instance or ip address to the domain then, due to some security reasons it will not update out .htaccess file (root and config both) . so the friendly url is not work with the domain.
Updating The IP Address Or Hostname
open your putty and paste this command(replace your domain name with NEW_DOMAIN eg. www.amazedplanet.com)
$ sudo /opt/bitnami/apps/prestashop/bnconfig --machine_hostname NEW_DOMAIN
Now you will check every thing is working: