Hi, newbie here… I set up a mail server on a clean VPS using Postfix/ Dovecot from Virtualmin. I am able to send and recieve mail normally using Roundcube webmail from “mail.mydomain.com”. Gmail and Outlook do not flag my address so I think I have set up the correct DNS records and SSL certs.
But when I try to connect to my server with an IMAP client from Outlook on Windows 10 or any iOS mail client (Gmail, outlook, even the basic Apple one) refuse to connect on SSL. Outlook was slightly helpful and said it was refusing to connect because of an “invalid trust chain”. What does that mean?
Thunderbird on Windows pulled all my settings down automatically. Now it did show a security warning saying that it was getting an unknown SSL cert and did I want to add an exception even though it was the LetsEncrypt cert. But it works fine otherwise can send and receive mail.
SSL certs are from LetsEncrypt for my domain and the mail server. Verified they are R3 I heard that was a big deal in some earlier posts. My IMAP is at mail.mail.mydomain.com because I am running mail servers under a “mail” subdomain. A little long but hey it works so I don’t want to change it. LetsEncyrpt gaive me vaild certs for all the alias associated to my mail subdomain (including mail.mail.mydomain).
I am lost as what to how to fix this please help!