Hello, so i was following up this guide on google; https://hostpresto.com/community/tutorials/how-to-setup-an-email-server-on-centos7/
Followed all instructions, and guide said to restart postfix/dovecot to apply changes, so i went ahead and when i tried to restart postfix, i recieved errors and it wasn't able to restart the process, i will include the error stack here, so maybe you could give me heads up whats going on there.
After doing postfix check
I got stack trace like

postfix: warning: unreasonable macro call nesting: "mydomain"
postfix: warning: unreasonable macro call nesting: ", localhost, "
postfix: warning: unreasonable macro call nesting: "mydomain"
postfix: fatal: dictionary mail_dict: macro processing error

Edited files (/etc/hosts, /etc/postfix/main.cf, /etc/postfix/master.cf, /etc/dovecot/conf.d/10-master.conf, /etc/dovecot/conf.d/10-auth.conf, /etc/dovecot/conf.d/10-mail.conf, /etc/dovecot/conf.d/20-pop3.conf

Now i will include my current code on these files, i will be using pastebin in that case.
Main.cf = https://pastebin.com/GvBy5jn9
Master.cf = https://pastebin.com/gCte9PJ0
10-master.conf = https://pastebin.com/UhH4bG0y
10-auth.conf = https://pastebin.com/Fa0yTCVX
10-mail.conf = https://pastebin.com/LhjxKa8D
20-pop3.conf = https://pastebin.com/zh1sRWEH