1.) I have an installed WordPress site on Digital Ocean
2.) I was able to login while the site was an IP address and not my domain name
3.) Now that the website is under my domain name, I cannot login in from the back end.

Example:

I go to domain.com/wp-login and it switches back to my IP address and doesn't accept my password I created with Digital Ocean. I can only login once I select "Forgot Password" and go through the song and dance of requesting a new password and then I can login.

But even then I can't see my site when I select "Customize Theme" nor can I preview pages as it reads that I do not have permission.

What's going on here?