Do Have to use virtualmin as a DNS Server in order to use it to send emails?

I’ve configured virtualmin to be my email server but not my DNS server. mxtoolbox.com tells me everything is fine. I can receive email but cannot send. What could I be doing wrong?

I am not running mine as a dns server and email works fine.

What network is your server on?

If it is google cloud compute, then the reason would be because you must use a mail relay service provider such as sendgrid. An ever increasing number of hosts are forcing that now due ro ip addresses getting blacklisted by idiot corrupt users sending too much spam on their networks.

If not google cloud, one check you should make anyway…are outgoing mail ports open on your server and on your network?

Thank you so much for your help. I’ve had some success since then. I’ve started some minor tests. It is sending now but GMail is sending it to the spam folder. Any suggestions are helpful.

How can I encrypt my outgoing email?

I followed this page https://www.virtualmin.com/node/40232. When I add “smtp_tls_security_level = may” to the config file I am then able to connect using STARTTLS on port 587. Except it gives me this error saying “my server does not advertise STARTTLS” I think I’m missing something. If I’m connecting on port 587 should I worry about 465? Where would I go to add the “Open port 465 in firewalld” command exactly?