trying to setup my centos server to send Zoho emails using Postfix. Everything is working correctly, except Gmail flags all the messages from my server (Postfix) as Spam. The SPF and DKIM records are set and verified. One thing I've noticed is that on Gmail, if I check the message headers, under authentication-results, it only lists the SPF and it's a pass. DKIM is not showing. Checking messages coming from a different server, it shows also DKIM as pass. 

Can someone point me in the right direction? The domain is devdan net.

Thanks,

Daniel M