Changing WP site from IP Address to domain name (Accessing Admin Problems)

I created a new WP site using a static IP address on a new hosting account. After the site was completed and ready to go live, I changed the DNS to point to the new host's name servers. I then edited the database table wp_options URL and home with the domain name, replacing the IP Address.
The site is coming up and working until I tried to login to the admin. I've tried both, and, and am getting this error:
Not Found
The requested URL /wp-login.php was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

I should also mention that for the first time, I created a child theme for this site. Everything worked fine before taking the site live and using the domain name. I am using the premium theme Enfold.

Can you please help me figure out what I've done wrong, and how to fix this?
Thank you so much,