I have a Multi-Network + Multi-Site w/ Subdomains installation & my subdomains aren't &quot

First & foremost, I'd like to thank you for your help, time and consideration in advance. I have been unsuccessfully working on getting this installation "up" for almost a year. (SMH- I'm so ashamed it took me this long to ask for help. :disappointed:)

Originally, neither the multinetwork or multisite worked for me. I used the power of Google & the WP site to find others who had the same problems and step-by-step eventually got the multi-network part "working".

My problem is that when I create a subdomain (on any of my networks)- I can not access the site or dashboard for the subdomain site. When I try to visit the subdomain or its dashboard, I receive a "404 Error File Not Found" error.

I have BlueHost & had them enable my wildcard. Also, I changed my domains from "add-on" to "parked" *(this is what made my multi-network actually start to work...). I've tried several plugins, several WP code changes, and have started over with a "fresh" install at least 2-3x's.

I don't know what else to do to make this work. Can you help me?

My wpconfig is:
define('MULTISITE', true);
define('SUBDOMAIN_INSTALL', true);
define('DOMAIN_CURRENT_SITE', 'mydomainname.com');
define('PATH_CURRENT_SITE', '/');
define('SITE_ID_CURRENT_SITE', 1);
define('BLOG_ID_CURRENT_SITE', 1);

My htacces is:
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# uploaded files
RewriteRule ^files/(.+) wp-includes/ms-files.php?file=$1 [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L]
RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule . index.php [L]