Unable to reply to email thread using Send Email node (SMTP node)

Questions
1

Describe the problem/error/question

I am trying to reply to an email that was itself a reply to my original message. However, I’m unable to maintain proper email threading because the SMTP node in n8n doesn’t allow setting email headers, particularly In-Reply-To and References.

What is the error message (if any)?

There’s no error message — the problem is functional: the reply is sent, but it doesn’t appear in the correct thread in email clients due to missing headers.

Please share your workflow

(Since it's not an error, the workflow includes a IMAP trigger, followed by an SMTP node sending a reply.)

Share the output returned by the last node

The email gets sent, but appears as a new conversation in Gmail rather than a threaded reply.

Information on your n8n setup

  • n8n version: 1.98.2
  • Database (default: SQLite): Default (SQLite)
  • n8n EXECUTIONS_PROCESS setting (default: own, main): Default (own)
  • Running n8n via (Docker, npm, n8n cloud, desktop app): Railway template (Docker-based deployment)
  • Operating system: Likely Linux via Railway (local OS is Windows)
2

I haven’t found a way to reply and maintain the thread, you may have to rely on API calls to do that.

3

I’ve made a custom node that allows you to set custom headers for SMTP mail.

A minimal reply chain example is in the README. Happy hacking!

2 Likes
4

Error installing new package

Error loading package “n8n-nodes-better-send-mail” :Failed to save installed package Cause: invalid input syntax for type integer: “2.2”

I got this error when I tried to install ‘n8n-nodes-better-send-mail’

5

Are you able to upgrade your n8n version? It works for me on 1.100.1.

I think they changed the version field to a float in one of those update because it’s like that in the original Send Email node.

6

My n8n version is 1.100.1 too.

7

Hey halkony, seems like another node creator had faced this same issue. Can you please check this out:

I’m not sure I understand this—could you take a look and see if it makes sense to you?

8

I understand it. I just pushed 0.1.2. See if that works on your end.

1 Like
9

Yes! v0.1.2 works. Thanks for the quick responses. And, I was successfully able to thread (reply) to an email too!

10

Glad to have solved the problem. People have been complaining about this for a while!

11

Halkony I must say you saved my life,

I was looking for a solution for Bulking email marketing, that means that a header “list-unsubscribe” is a must-have.

didn’t want to rely on api calls and mime.

12

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.