I have a problem with Mailcow; I cann’t send mail but can receive it. I have tried to send emails using built-in SOGo app and with Apple Mail. In both cases, the email goes into the sending queue but is not sent.
Mailcow is installed according to the original documentation on a clean Debian 11 system. The Hetzner Cloud server was created before installing Mailcow and not used before.
Initially, I couldn’t even receive mail, but after reading the Mailcow documentation and searching in Google, I contacted Hetzner’s support and asked them to open the ports from this manual (https://docs.mailcow.email/prerequisite/prerequisite-system/#firewall-ports). This was 20 hours ago. About 20 minutes after contacting support, I starting receive emails (even got a few test emails sent a couple of hours before contacting support). But I still can’t send email.
Just in case, I checked the ports using the nc command from my laptop. It seems they are open.
I also tried double-checking the DNS records (they based on DigitalOcean). It seems everything is in order.
Additionally, I looked at the postfix logs but couldn’t understand the exact problem. For some reason, Google replies with “Connection timed out.” But it happens immideatly after I try to resend emails
What could be the problem? How can I set up sending mail?