How to debug correctly?

[LoranA]

Hi!

I’m pretty new to N8N but I’ve used Make / Integromat / Zapier a lot.
I’ve a flow that gets ±10K records from MySQL and does a POST to an API based on those records. When this if running i’m getting the error “JSON parameter need to be an valid JSON”. From those 10K records I can see that ±1000 are getting trough without any issues. But it gets stuck on one record.

I’ve enabled log_level=debug with an output to console, but in the error there is no actual data on what is happening.

All I see is:

"event": "Instance FE emitted error",
        "properties": {
            "error_title": "Problem in node ‘[NAME] POST User‘",
            "error_message": "JSON parameter need to be an valid JSON",
            "caused_by_credential": false,
            "workflow_id": "[ID]",
            "version_cli": "1.41.1"
        },
        "integrations": {
            "All": true
        },

Is there a better way to find out what POST data triggered the error?

Thanks!

N8N Version: 1.41.1, Docker,

[n8n]

It looks like your topic is missing some important information. Could you provide the following if applicable.

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

[barn4k]

hello @LoranA

Can you share the JSON parameter need to be an valid JSON error? usually it has an item index, by which you can find the referenced input. You can also use the Loop Over items node to see how the items get processed one-by-one for better visibility.