resolve dkim=unknow on yahoo

Job ID: 37492088

Budget: $10 – $30 USD

Hi,
I am running a Postfix server along with 2 DNS servers. I had to change the the IP address of mail server. After changing the IP I got DNS entry updated including SPF. Everything is working fine but when I send a mail to yahoo it's going to spam and it shows "dkim=unknown". So this need to be resolved.
Related categories: System Admin Linux DNS Email Handling Postfix