smtp server configuration

[Nico]

Hello,
I've checked lots of messages, but I fail to find the answer I'm looking for.
I've tried to set Mailgun (successufully) with all MX, SPF, DKIM, records needed.
But the smtp does not work
The main domain is handled at Cloudflare. (so no proxy activated)
I've created a mail in mailboxes Cloudron "mail@domain.com".
While I test the build in smtp server, I've got an error, but I need to open the port 25 (it's going to be fixed)
Butin the same time I wanted to test mailgun further, and here I do have a connection timeout on the smtp config panel.

What should I test to activate it ?

Purpose is to activate n8n (mainly) notifications, or Stirling notifications (if applicable) on errors, or Uptime Kuma,on password reminders.

I also notice that the MX test fail from time to time, while refreshing, it's getting green again, but on first load, it might be red.

Thanks for your help !

[girish]

@Nico If I understand correctly, you have configured mailgun as a relay on Cloudron - https://docs.cloudron.io/email/#relay-outbound-mails . Is that correct? What port have you configured for the relay? You must use port 587 (STARTTLS).

[crazybrad]

@Nico Postmark is excellent and Cloudron supports them. We are using them for all SMTP traffic. And their process for creating "server credentials" is easy and straightforward. If you add the required DKIM and PTR records for a domain, any sender from that domain is authorized.

[Polynox]

Nico you should have a look at Amazon SES and Labnify SMTP. Both are very easy to setup and Cloudron supports them. As with most email service providers, you need to add the required DKIM records to your domain's DNS settings; these records add a digital signature to each outgoing email, which can be verified by the recipient's server to confirm that the email hasn't been tampered with and originates from an authorized sender. Next, just as crazybrad already pointed out you must configure PTR (Pointer) records in the DNS settings, which are used for reverse DNS lookups allowing IP addresses associated with your domain to be resolved back into hostnames—this step is crucial because it ensures your messages aren’t flagged as spam by recipient servers due to mismatched information. Once these DKIM and PTR records are correctly set up, any sender using an email address under that domain will automatically gain authorization, meaning they can send emails seamlessly without additional verification steps or complex configurations while maintaining robust security standards.

[brayden212]

Yes, you’re correct! If you’ve configured Mailgun as a relay on Cloudron, you should use port 587 with STARTTLS for secure email sending. If you're looking for alternatives, I recommend SMTPget and iDealSMTP. Both offer reliable services and can also be easily configured for your email needs.