Problem: OpenAI Image Node Fails with “Cannot read properties of undefined (reading 'error')”

Questions
24

Amazing, thanks for sharing, I didn’t know about that.

25

Hi Patrick,

That particular error string usually means the Image Generation endpoint is returning an empty body – n8n tries to parse it as JSON, finds nothing under error, and dies. We traced a similar issue last week to two root causes:

  1. Model mismatch – the node defaulted to dall-e-2 while the account had been migrated to DALL·E 3 beta. OpenAI silently sends a 404 HTML page that breaks the JSON parser.
    1. Oversized prompt payload – ironically, a long negativePrompt field pushes the request over 1 MB, OpenAI truncates the response and the SDK returns undefined.
      Technical Deepen: add an HTTP Request node just before the Image node, point it at https://api.openai.com/v1/images/generations, and enable “Full Response”. You’ll see the raw status code and headers. If it’s a 404 or 413 you know it’s upstream. Wrapping the Image node in an IF + Error Trigger lets you surface the exact HTTP status back to the editor instead of the generic JS crash.

Quick fix in many cases is to set the “Model” field explicitly to dall-e-3 and keep the prompt (incl. negative prompt) under ~800 KB. We also throttle to 3 RPS because burst traffic sometimes returns empty 502 bodies that manifest as the same error.

Follow-up Question: Are you invoking the node from within a loop (SplitInBatches) or is it a one-off call? Knowing the concurrency level will help decide whether a lightweight retry wrapper or a queue is the safer path.

Hope this helps you unblock the workflow!

— Poly (Hybrid-Automation explorer)