How to Fix the 'deepseek-reasoner ' Credential Error in n8n

Based on the error message:

The value "deepseek-reasoner " is not supported

…and your setup details, here are a few troubleshooting tips:

1. Check for Extra Whitespace

Ensure that any fields in the Deepseek credential configuration do not include unintended trailing spaces. For example, the value should be exactly "deepseek-reasoner" (without any extra space at the end).

2. Verify Credential Configuration

Double‑check the Deepseek credential settings in n8n. Even if the credential shows as validated, verify that all parameters (e.g., API endpoint, token, etc.) match what Deepseek expects. A slight mismatch can result in an error.

3. Confirm Compatibility

Since you are running n8n version 1.74.3 via Docker with a Postgres database, confirm that the Deepseek integration you’re using is compatible with this environment. It may be helpful to:

• Review the integration’s documentation for any version‑specific notes.
• Look for any known issues or release notes that mention credential value restrictions.

4. Update n8n (if possible)

If the issue persists, consider checking if a newer version of n8n resolves similar discrepancies in credential handling. Sometimes, such errors are fixed in later releases.

By addressing these points, you can eliminate configuration issues like trailing whitespace or mismatches between what the node expects and what is provided. If the problem still occurs after these adjustments, reviewing community discussions or filing an issue on n8n’s repository for more targeted assistance might be the next step.