Is there a way to see all outgoing emails in Postal Mail Server?

I am using Postal and all is going well but suddenly Google is soft failing me for sending too many messages, but I haven't sent very many!

I want to check if someone unauthorized is using the server as a relay, but I couldn't find any mail.log in /var/log and the postal log is empty.

How can I find all emails being sent from this server? The OS is Ubuntu 18.04 LTS

Thanks!