Can send emails via clients with valid DKIM

I have set up postfix on my ubuntu server. All the necessary DNS records are set here in Cloudflare. My Server can send emails with valid DKIM but not any email client like gmail. Both are configured to use as the smtp server.

it sounds like your postfix server is using as a smarthost relay. If your postfix server is performing the DKIM signing, it would explain why your Gmail messages are lacking the expected DKIM signatures. If the valid DKIM signatures are being applied by, you will need to work with that server’s configuration to determine why it is not signing your domain emails sent from your Gmail.

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Hi Volkan3915

When i am using Dkim Lookup , for your domain I am not seeing any Dkim key, so google will drop. They need vaild Dkim And Dmarc keys to send.
Thank you

I am sorry for confusion. My domain is My hosting provider is So I am using the smtp-server of my hosting provider.

I have set up my domain email in gmail and configure the on port 465 as my smtp-server, which I am using also in my postfix configuration as relayhost. In order to sign the outbound emails of my website I followed along this tutorial

That means only my postfix is able so sign my emails and no one else?

Correct. Updating your GMail settings to use an account on your Postfix server, and you should wind up with DKIM signed email.