Trouble with SMTP configuration on port 587 - 504 5.7.4 Unrecognized authentication type

Hi there,
I’m having trouble setting up SMTP credentials using port 587 (using user/password and STARTTLS). N8N’s test is returning: Invalid login: 504 5.7.4 Unrecognized authentication type.
This seems to work though:

  • podman exec -it n8n-app sh
  • openssl s_client -starttls smtp -connect :587
  • EHLO test
  • AUTH LOGIN
  • User/Password

Describe the problem/error/question

Setup of SMTP credentials using port 587 with user and password with STARTTLS.

What is the error message (if any)?

Invalid login: 504 5.7.4 Unrecognized authentication type

Please share your workflow

Share the output returned by the last node

Information on your n8n setup

  • n8n version: 1.118.2
  • Database (default: SQLite): postgresql
  • n8n EXECUTIONS_PROCESS setting (default: own, main): -
  • Running n8n via (Docker, npm, n8n cloud, desktop app): podman
  • Operating system: Debian 13

please someone already fix it or not ?