The problem:
Today I went to rubyat.com/blog and got an error message claiming
/etc/wordpress/config-xxxx.com.php could not be found. The file is either not readable by this process or does not exist. Please check if /etc/wordpress/config-xxxx.com.php exists and contains the right password/username.
Something changed so that /etc/wordpress/wp-config.php is no longer viewed as the default. The fix is to find the correct file name for the default and create a symbolic link to that default.
The solution:
cd /etc/wordpress
ls
sudo ln -s wp-config.php config-default.php