I server can send mail to gmail, yahoo, but not outlook and hotmail, why?

I am new at linux, I build my mail service in CentOS using postfix, dovecot and squirrelmail, I can send email to gmail, and yahoo, although some of them are in spam, but my outlook, and hotmail cannot receive any mail. Also, my service cannot receive any mail, even from myself, anyone can teach me ?

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the server can send mail to Gmail, but not yahoo. This problem is the same with me, after test my whole setting, my problem is not solved after I found Yahoo Helpline Number +1-(833)-222-2937. After talking to Yahoo executive my problem is solved.

Could you please paste the DNS records related to your mail server here?


When it comes to successfully sending and ensuring successful receipt of your e-mail, you’ll need to setup SPF and DKIM for your domain and ensure that Postfix is capable of using it. Without these two things, most e-mail to providers such as Google, Yahoo, Hotmail, Outlook, etc will all land in SPAM as there’s no validation to confirm that who is sending the mail is actually who they say they are.

There’s a really good guide on how to setup both. It’s written for Debian/Ubuntu, though you’d simply need to adjust the packages to match those available to CentOS.

The configuration in the guide, however, should apply and work for any OS.