Weird Port 80/404 Error

(Actually running WP 2.7, but no option for it in the Version scrolldown)

Couldn’t remember my password, so I un-installed WP and re-installed it.

When trying to log in, I get the following error:
404 Not Found
The server can not find the requested page:
https://MYDOMAIN.COM/wp-admin/index.php (port 80)

When I FTP into the site, the file definitely exists (even after refreshing folder).

Any advice?

Thanks…