I can send emails but i cant receive any except when sent from my server (Ubuntu 14.04, Postfix/Dovecot)

Hi, i followed this tutorial to install a mail server : https://www.digitalocean.com/community/tutorials/how-to-configure-a-mail-server-using-postfix-dovecot-mysql-and-spamassasin

I run on Ubuntu 14.04, use pop3 and i created my own certificate using this link suggested by @ashley588197 (thanks) : http://www.eclectica.ca/howto/ssl-cert-howto.php

I can now send emails but i cant receive any except when sent from my server (same adress) I think it could be a certificate issue, as i think an email sent from the same server is automatically considered “authentified”.

When i try to add my new email to my gmail account, here is the mail.log width SSL on 995

dovecot: pop3-login: Disconnected (no auth attempts in 0 secs)

The same without SSL on 110

dovecot: pop3-login: Disconnected (tried to use disallowed plaintext auth)

I then tried to change in /etc/dovecot/conf.d/10-auth.conf :

disable_plaintext_auth = no
auth_mechanisms = plain login

But still the same issue Some help would be very appreciate

Thanks Vincent