Postman issues

Questions
1

I keep giving the Same request and it works in Postman, but fails inside n8n with auth errors.

Describe the problem/error/question

What is the error message (if any)?

Please share your workflow

(Select the nodes on your canvas and use the keyboard shortcuts CMD+C/CTRL+C and CMD+V/CTRL+V to copy and paste the workflow.)

Share the output returned by the last node

Information on your n8n setup

  • n8n version:
  • Database (default: SQLite):
  • n8n EXECUTIONS_PROCESS setting (default: own, main):
  • Running n8n via (Docker, npm, n8n cloud, desktop app):
  • Operating system:
3

It’s probably cause n8n is probably not sending headers exactly the way you think.

you can fix it by

  • Checking if headers are actually being passed (not just set in UI)
  • Avoiding hidden whitespace in API keys
  • Using “RAW headers” instead of relying on credential helpers when debugging

Most of the time, it’s a silent formatting issue and not the API itself.