Answer: Send a non-empty
title string on POST /api/youtube/post. Map the n8n field explicitly - empty expressions are the most common cause.YouTube docs · YouTube workflow
What this means in a real publishing workflow
YouTube uses the same invalid-title response for an empty title and some titles that violate metadata rules. The most common Postifys cases are an unmapped n8n expression or a final title longer than YouTube’s 100-character limit.
Recommended implementation
- Inspect the exact title sent by the YouTube node, not only the source-table value.
- Trim whitespace and require at least one visible character.
- Count hashtags or prefixes appended by the workflow.
- Keep the final title at 100 characters or fewer, then create a corrected submission.
How to verify the fix
Use an n8n expression such as String($json.title || "").trim().slice(0, 100). Put additional hashtags and context in the description. Retrying an existing failed event preserves its old title unless the source is rebuilt.
Operational check: Test with one item, confirm the final destination and Postifys history state, and only then enable the recurring workflow. Keep the returned Postifys ID beside the source row so every result remains traceable.
Related Postifys resources
API documentation · Error reference · n8n automation guide · Safe retry guide · Compatibility matrix