Debug My N8N Workflow Errors

I’ve built a workflow-automation stack inside n8n, but I keep stalling on two recurring pain points: node-level errors and stubborn API-key credential failures. Most of the flows run, yet a few nodes throw red-flag messages, and whenever the chat/AI node hands off data the whole chain collapses.

Here is what I need from you:
• Jump on a screenshare (or similar) to trace the exact error messages inside the failing nodes.
• Pinpoint why my stored API keys refuse to authenticate and walk me through the correct credential setup so future keys stick.
• Suggest any best-practice tweaks that keep the workflow stable once the chat node fires.

I already understand the basics of n8n; I’m looking for medium-level, practical guidance rather than a ground-up tutorial. As soon as the workflow executes end-to-end without errors—and the credentials test green—we’re done. If you speak Portuguese that’s a plus, but English is fine.

Please tell me when you’re available and what remote-debug tools you prefer.