Use an SMTP relay

nouipoz

Hello everyone,

I’ve set up a Mailcow server, but nowadays, getting a good IP reputation and ensuring proper email deliverability across all providers is quite challenging.

So I wanted to use an SMTP relay (Mailjet), which I configured under “Add a relay host”.

However, when testing with Mail-tester, the email is correctly sent through Mailjet’s SMTP, but both DMARC and DKIM fail.
Yet I did configure everything using the data provided in the Mailjet dashboard.

Do you have any idea where the issue might come from?
Or perhaps another solution to ensure emails are properly delivered to all major email providers?

Thanks for your help :-)

esackbauer

You should take care that either mailjet or mailcow send DKIM data, not both. and that you set the DNS records properly to that configuration.
You need to enable or disable accordingly. To disable in Mailcow delete the keys.

nouipoz

esackbauer
Hello,
Thank you for taking the time to reply.
DKIM does appear to be properly disabled for the domain in question in Mailcow, though :

Thanks in advance.

DocFraggle

esackbauer To disable in Mailcow delete the keys.

👆

nouipoz

Hello,

I would like to revisit the topic. Has anyone on the forum managed to get mailcow working with sending via an SMTP relay? (with DKIM OK)

Thank you for your help 🙂

esackbauer

Yes. I did use smtp2go mail relay.
Have you checked the documentation on mailjet how to setup DKIM properly?
Most likely you did something wrong which is not mailcows fault.

nouipoz

esackbauer Hello, thank you for your response. How did you disable DKIM in mailcow? Did you do it as shown in my screenshot in my previous message? Thank you for your help 🙂

nouipoz

DocFraggle "I have successfully deleted the key in Mailcow, but when I send an email from the webmail, it does not use the DKIM key from Mailjet; instead, it uses the old one generated by Mailcow.
Mailjet confirms that my DNS configuration is correct :

DocFraggle

nouipoz It’s possible that you have to restart the stack after deleting the key

docker compose down
docker compose up -d

nouipoz

DocFraggle

Thank you for your help, but unfortunately, I have already done this. Is it normal for it to appear like this in Mailcow?

esackbauer

nouipoz Is it normal for it to appear like this in Mailcow?

No, this is wrong. It should only show the same names as the configured mail domains.
Either you tried to setup such a mail domain in a wrong way, or your mailcow is broken.

nouipoz

esackbauer It does appear correctly with the configured domain name (I just hid the domain to avoid spam). But is it normal for it to say “missing key” ?

esackbauer

nouipoz is it normal for it to say “missing key” ?

yes.

nouipoz

esackbauer Thank you for your response, In this case, I believe my Mailcow configuration is correct. How can I explain that the DKIM key used when I send an email from the webmail is the one from Mailcow?

esackbauer

https://community.mailcow.email/d/5004-use-an-smtp-relay/5

nouipoz

esackbauer As mentioned in my previous message, Mailjet confirms that everything is fine. Therefore, I believe the issue is with Mailcow.

esackbauer

https://community.mailcow.email/d/5004-use-an-smtp-relay/2