Spamassassin and Email problem(s) on newly installed CyberPanel

Hello,

I am new to CyberPanel and installed it on the new VPS server. Everything is fine except the email system. I have some problems and need help with them.

  1. Send/receive problem: When enabled Spamassassin, I can send emails from VPS to outside but I can’t receive emails from outside (I can receive from inside). This occurs when the Spamassassin filter is enabled. If I enable the “-o content_filter=spamassassin” in postfix/master.cf, emails begin to stuck on queue and after 4 hours they give error “Deferred: Connection refused by mail.domain.com”. If I remove the “-o content_filter…” extension from smtp line in masfer.cf, I can send and receive emails both inside and outside of the server. If the Spamassassin enabled in master.cf the email log shows that “Jul 25 20:06:47 vps opendkim[507]: 9BCBF882BE: bad signature data”. I don’t know if this is related to stuck emails.
  2. I am using email services like Zoho, Yandex and etc. I have created two domains under CyberPanel. For domain1 mail domain is enabled and for domain2 not enabled (I don’t know why and I can’t remove the mail domain from panel). When I click list emails button for domain2, “No emails exist for this domain.” error appears. For this domain, I am able to send emails from VPS to this domain’s email. When I click the list emails button for domain1, the panel shows me the email settings. But for this domain, I am not able to send emails from VPS. Mailer-daemon says no email account found. But both domains use Yandex and are configured for Yandex.
  3. I have changed the settings too many times to try different ways to solve the problems. I couldn’t find a successful solution. While I am trying these, I realized that when I restart the VPS, postfix does not start auto. I have created a symlink for boot, and changed the ownership but no success.
  4. My VPS is configured for domain vps domain com, and can I use the Mailgun or etc for Mailer-Daemon mails? If so, how?

Can you please help me about these problems?

Thanks.