Unable to setup a functional SMTP account with local cloudron mailbox

[overclockmp]

Hello everyone,

I am currently trying to setup a send email node in n8n.
I have done what was suggested here and I created a specific user for this. I have also setup a mailbox associated to that user.

Outbound emails work fine already with any apps (relay through mailjet).
I have added the new user email as a sender in mailjet config.

I have used the credentials from that new user to setup the n8n SMTP account.
I use port 587 and mail.<domain> as the host.
SSL is disabled and STARTTLS is enabled.

I have also added the client host name as the n8n hostname.

Is there a better way to do this now? (this linked post is from 2021, so maybe this information is outdated).
Is there something I missed?

Thank you all for your help

[joseph]

@overclockmp I would say first test using swaks. Open a web terminal and use swaks to test your credentials. Something like:

swaks --server my.domain.com -p 587 --from "from@domain.com" --body "Test mail" --auth-user "from@domain.com" --auth-password "password"

[overclockmp]

Hi @joseph, thanks for the assistance.
Running the command above with --server mail.domain.com, I get "Network Unreachable".
Running it with --server my.domain.com, I get "Connection Timeout".
Under Email > Domain > Status, the outbound SMTP is green.

The more I look into this, the more it seems that I would have to use mailjet directly instead of going through the outbound SMTP, but I am not sure if it's a good approach.

[overclockmp]

Hello , just following up here to see if there are any other ideas...
Thanks for the help

[james]

Hello @overclockmp
Could you please share a screenshot of your N8N configuration for SMTP?

[joseph]

@overclockmp said in Unable to setup a functional SMTP account with local cloudron mailbox:

Running the command above with --server mail.domain.com, I get "Network Unreachable".
Running it with --server my.domain.com, I get "Connection Timeout".

I would start here... Can you ping/host/dig mail.domain.com ? Can you telnet mail.domain.com 587 ?

[overclockmp]

Apologies for the delay, I must have missed the notification with the holidays. Thanks for your answer.

@joseph,

Can you ping/host/dig mail.domain.com?

Yes, using dig from n8n web terminal:

# dig mail.domain.com
; <<>> DiG 9.18.30-0ubuntu0.24.04.2-Ubuntu <<>> mail.domain.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27695
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;mail.domain.com.               IN      A

;; ANSWER SECTION:
mail.domain.com.        0       IN      CNAME   my.domain.com.
my.domain.com.  0       IN      A       192.168.1.3

;; Query time: 44 msec
;; SERVER: 127.0.0.11#53(127.0.0.11) (UDP)
;; WHEN: Sat Dec 27 16:19:45 UTC 2025
;; MSG SIZE  rcvd: 81

Using host from n8n web terminal:

# host mail.domain.com
mail.domain.com is an alias for my.domain.com.
my.domain.com has address 192.168.1.3
my.domain.com has IPv6 address 2606:4700:130:436c:6f75:6466:6c61:7265

Can you telnet mail.domain.com 587?

No, it hangs and times out on the web terminal and connection is refused through ssh:

# telnet mail.domain.com 587
Trying 192.168.1.3...
Connection failed: Connection timed out
Trying 2606:4700:130:436c:6f75:6466:6c61:7265...
telnet: Unable to connect to remote host: Network is unreachable

It is probably worth noting that I am using a pihole as local DNS. Not sure if it has any impact...

[overclockmp]

Hi @james, here is a redacted screenshot that should match my description at the beginning of this thread: