n8n Workflow Error: How Can I Debug 'Cannot Read Properties of Undefined (reading "node")'?

Below is some guidance on diagnosing this error:

Likely Cause

The error message "Cannot read properties of undefined (reading ‘node’)" indicates that somewhere in your workflow an expression is trying to access a property on a node that doesn’t exist or hasn’t executed yet. This often happens if:

• You have an expression like {{$node["Some Node"].json["someProperty"]}} and the referenced node either hasn’t run (or didn’t produce output) or its name is misspelled.
• There’s a misconfiguration in the workflow wiring such that the supposed predecessor node was skipped.

How to Troubleshoot

1. Check the Execution View:
   Open the Executions log in n8n and select the failed execution. Review the read-only execution view to pinpoint on which node the error occurred. This will help you identify which part of your workflow is causing problems.

2. Review Expressions:
   Look at any expressions accessing previous nodes’ data. Verify that:

   • The node referenced in your expression exists and is correctly named.
   • The node has successfully run and produced output before the expression is evaluated.

3. Test Nodes in Isolation:
   If you suspect a particular node, try running that node individually (or use manual testing if applicable) to ensure it returns the expected data. Alternatively, add a Stop and Error node to see if you can throw a custom error confirming your suspicion.

4. Check Workflow Order:
   Ensure that your workflow connects nodes correctly so that any reference to a previous node is valid—this includes verifying the order of execution. The error indicates a referenced node might not have executed in time or at all.

By carefully reviewing these items, you should be able to identify whether it’s a misconfigured expression or a wiring issue. Once the problem is isolated, adjusting the expression or reordering the nodes should resolve the error.