Cannot read properties of undefined (reading 'message')

[leelisi112]

Bug Description

When running a chat-based workflow in n8n (Docker self-hosted), the workflow fails during execution at the Image Prompt Generator node.

The node throws a runtime error:

Cannot read properties of undefined (reading 'message')

The error occurs even though the workflow is correctly triggered by “When chat message received” and receives a valid user message. Execution stops immediately at the Image Prompt Generator node, preventing all downstream nodes from running.

This suggests that the Image Prompt Generator node assumes the presence of a message field in its input, but the actual input provided by the chat trigger does not include this field (or uses a different schema).

1. The issue appears to be caused by a mismatch between:

2. The output schema of When chat message received

And the input schema expected by Image Prompt Generator

To Reproduce

1. Run n8n in a Docker self-hosted environment

2. Create a new workflow

3. Add a When chat message received trigger

4. Add an Image Prompt Generator node

5. Connect the chat trigger directly to the Image Prompt Generator

6. (Optional) Connect an OpenAI Chat Model and Structured Output Parser as shown in the screenshot

7. Activate or manually run the workflow

8. Send any chat message (for example: Generate a banana image)

The workflow fails at the Image Prompt Generator node with the error:

Cannot read properties of undefined (reading 'message')

Expected behavior

The Image Prompt Generator node should correctly receive the chat message from the When chat message received trigger and generate a valid image prompt.

If the required input field (such as message) is missing or renamed, the node should:

• Either map the correct field automatically

• Or fail gracefully with a clear validation error indicating which input field is missing

Under no circumstances should the workflow crash due to an unhandled undefined property access.

Debug Info

Additional notes

The workflow is triggered correctly by the chat trigger.

The error occurs consistently and is fully reproducible.

Restarting the container does not resolve the issue.

Other workflows not using Image Prompt Generator continue to function normally.

Operating System

mac

n8n Version

2.0.2

Node.js Version

22.21.0

Database

SQLite (default)

Execution mode

main (default)

Hosting

self hosted

[n8n-assistant]

Hey @leelisi112,

Thank you for reaching out! We’ve received your issue and are looking into it. To help us track this internally, we’ve created a Linear ticket with the reference: "GHC-5945".

We’ll keep you updated as we make progress, but if you have any additional details or context to share, feel free to add them here - it’s always helpful!

Thanks for your patience and for bringing this to our attention.

---

For INTERNAL use only: GHC-5945

[MookieLian]

Thank you for reaching out! It looks like this issue might be more of a support request rather than a bug report. For general support, troubleshooting, or questions, we recommend raising your request on our community support forum.

The forum is a great place to connect with both our team and other community members who can help out. You might even find answers to similar questions there!

For issues related to n8n cloud billing or instances going offline please email help@n8n.io as we are not able to access your cloud account or workflows from these issues.

We'll go ahead and close this issue to keep the tracker focused on bug reports. Feel free to join the conversation on the forum, and let us know if you have any further concerns or questions.

Thanks again for being part of the n8n community!

#closed:support-issue