Setting up email (encryption?)

Hi !
I want to create email system in local network .usually local network email system use plain formate for authenticating their password.so i am not able to send mail locally from erpnext .how can i setup email in erpnext?

Have you seen this?

https://frappe.github.io/erpnext/user/manual/en/setting-up/email/email-account

Do you get any errors while setting up email?