Sending emails with TLS Selected

[Conor McCracken]

Hi

When I select TLS when sending outgoing mails I get the message

Can't verify identity of server: HOSTNAME OF MAILSERVER

I then did the following
Exported the Certificate from our Postfix Servers in a DER Format

keytool -import -alias ALIAS -keystore /opt/atlassian/jira/jre/lib/security/cacerts -file CERTFILE.cer

Then also just incase
cp CERTFILE.cer /etc/pki/ca-trust/source/anchors/
update-ca-trust

Stopped and restarted Jira but still getting the same message

I did the same steps for the Root CA Certificate but still get the same message

Just wondering if anyone has got Outgoing Email with TLS  working with Postfix

Thanks