Why am I getting connection refused error when typing my IP address /webmail after setting up squirrelmail, postfix and dovecot on centos7?

To build the email server I followed this article: https://hostpresto.com/community/tutorials/how-to-setup-an-email-server-on-centos7/

Basically, I want to build an email server using Apache, Postfix, and Dovecot with the squirrelmail as the webmail service. When I finish the instructions in the article provided above I go to the IP address/webmail and get a connection refused error in my browser. I know that Apache is working since I get the proper test page when going to the IP address. I have configured the DNS properly as well with the domain name.

I looked into it further and found something about a default firewall that comes with the centos7 clean install. So i tried to open it up by using the commands in the article: firewall-cmd --permanent --add-service=smtp firewall-cmd --permanent --add-port=587/tcp firewall-cmd --permanent --add-port=465/tcp firewall-cmd --permanent --add-port=110/tcp firewall-cmd --permanent --add-service=pop3s firewall-cmd --permanent --add-port=143/tcp firewall-cmd --permanent --add-service=imaps firewall-cmd --permanent --add-service=http firewall-cmd --reload

However the firewall-cmd command is not found.

I don’t know what else to try to get this thing going or if there is a setting on the droplets that are preventing me from doing this. Usually google helps but I have run out of stuff to search for. Any help is greatly appreciated! Thank you :)

I am using the most basic droplet (1g) with centos7