Sorry if I'm missing something but I have permissions set properly according to that article.

php files set to 644
folders set to 755

Should I just turn off message notifications? Or is there actually something incorrect about my permission settings?

try to set 444 for php files

You should to ask your hosting provider why they disabled function proc_open() on your host.  Some hosting providers do that by security reasons.
Or ask them how to enable it via cPanel.
Also you can try to setup dsn inside your system/config.php file and change mailer setting on admin-side to "take from config"

// details about allowed DSN settings  https://symfony.com/doc/6.0/mailer.html#transport-setup
const MAILER = [
    //'dsn' => null,
    // OR
    'protocol' => 'smtp', // or ses+smtp, gmail+smtp, mandrill+smtp, mailgun+smtp, mailjet+smtp, postmark+smtp, sendgrid+smtp, sendinblue+smtp, ohmysmtp+smtp
    //we use "username" also as ID, KEY, API_TOKEN, ACCESS_KEY
    'username' => 'merchant@yourdomain.com',
    'password' => '****super-secret-password****',
    'host'     => 'your-hostname',
    'port'     => 465 //or 587 etc
];

disable_functions   exec,passthru,shell_exec,system   exec,passthru,shell_exec,system
sendmail_from   no value   no value
sendmail_path   /usr/sbin/sendmail -t -i   /usr/sbin/sendmail -t -i

The setting for mailer is inner mailer

so wierd. I cannot to replicate this bug on my host with the same settings.
Can you help me with debugging?
Please replace your file public_html/core/lib/mail.php
with attached.  ( added trace in the error message ).
Then replicate the error and post error message here.
Thank you.

I would have to create thousands of products twice. I would rather edit a few lines of code and have it do what I want. I just don't know which lines of code control the price display while logged in.

I do appreciate you taking time to answer though. Thanks!

https://github.com/abantecart/abantecart-src/blob/master/public_html/storefront/model/catalog/product.php#L1560

Coming back around to this again.

Could someone please point out what part of product_listing.tpl would need to be edited to get the correct group discount pricing to display on both the category page and the product page?

I know that I could make the price a special instead of a discount but that automatically puts them on the Specials page and shows the "Sale" text which I don't want.

Thanks!

You should no to edit tpl file in this case.
Is question only in Specials page?
What if remove links on it and use Featured block instead?
If you have a special price of product for group it's a "special". When you wish to show special product but say it's not a special product it sounds wierd

try to remove all messages. i guess nofitication depends on repeating

Your contactUs form works as expected.
I created new customer, changed store email to mine
and i got this email to another mailbox address.
See screenshot