n8n - 💡(How to fix) Fix OpenAI credential fails on n8n Cloud 2.19.5: config.headers.setContentType is not a function [3 comments, 3 participants]

Describe the problem/error/question

I’m using n8n self-hosted with Docker on version 2.19.5.

I’m trying to connect OpenAI credentials in n8n, but the credential test fails.

OpenAI setup seems valid:

• New API key created
• Credits are active on my OpenAI account
• Organization ID is left empty
• Base URL used: https://api.openai.com/v1
• API key has read/write permissions

The issue seems to happen inside n8n before the OpenAI request completes correctly.

What is the error message (if any)?

The error message shown in the OpenAI credential window is:

config.headers.setContentType is not a function

Please share your workflow/screenshots/recording

I’m testing with a very simple workflow:

Manual Trigger → OpenAI “Message a model” node

The error happens when trying to connect/test the OpenAI credential.

Screenshot attached if needed.

Share the output returned by the last node

No output is returned because the OpenAI credential connection fails before the workflow can execute correctly.

Debug info

core

• n8nVersion: 2.19.5
• platform: docker (self-hosted)
• nodeJsVersion: 24.14.1
• nodeEnv: production
• database: sqlite
• executionMode: regular
• concurrency: -1
• license: enterprise (production)

storage

• success: all
• error: all
• progress: false
• manual: true
• binaryMode: filesystem

pruning

• enabled: true
• maxAge: 336 hours
• maxCount: 10000 executions

client

• userAgent: mozilla/5.0 (macintosh; intel mac os x 10_15_7) applewebkit/537.36 (khtml, like gecko) chrome/148.0.0.0 safari/537.36
• isTouchDevice: false

Generated at: 2026-05-10T16:40:02.819Z