What causes "An error occurred during file upload." in danny-avila/LibreChat?

Check server logs — logAxiosError logs the detailed axios error before this generic throw.

An error occurred during file upload.

Error message

An error occurred during file upload.

What it means

Thrown by uploadVectors in its catch block as a last-resort wrapper for any error that occurs during the vector upload process. This catches errors from the axios POST to the RAG API, the response parsing, or the known_type/status checks (errors 116 and 117 are re-thrown and caught here). The thrown error uses the original error.message if available, or falls back to a generic message. logAxiosError is called first for detailed logging.

Source

Thrown at api/server/services/Files/VectorDB/crud.js:118

      throw new Error(`File embedding failed. The filetype ${file.mimetype} is not supported`);
    }

    if (!responseData.status) {
      throw new Error('File embedding failed.');
    }

    return {
      bytes: file.size,
      filename: file.originalname,
      filepath: FileSources.vectordb,
      embedded: Boolean(responseData.known_type),
    };
  } catch (error) {
    logAxiosError({
      error,
      message: 'Error uploading vectors',
    });
    throw new Error(error.message || 'An error occurred during file upload.');
  }
}

module.exports = {
  deleteVectors,
  uploadVectors,
};

View on GitHub (pinned to 5ff282f900)

Solutions

Check server logs — logAxiosError logs the detailed axios error before this generic throw.
Verify RAG_API_URL is reachable from the app server (curl or health check).
If the underlying error is error 116 or 117, address those specific conditions.
For network errors, check firewall rules, DNS resolution, and RAG API container health.
Consider preserving the original error type rather than wrapping, so callers can distinguish unsupported-type errors from network failures.

Example fix

// Note: the current catch block wraps ALL errors, losing the specific
// known_type/status messages. Consider rethrowing those:

// before
} catch (error) {
  logAxiosError({ error, message: 'Error uploading vectors' });
  throw new Error(error.message || 'An error occurred during file upload.');
}

// after — preserve specific errors
} catch (error) {
  logAxiosError({ error, message: 'Error uploading vectors' });
  if (error.message.startsWith('File embedding failed')) {
    throw error; // preserve specific message
  }
  throw new Error(error.message || 'An error occurred during file upload.');
}

Defensive patterns

Strategy: try-catch

Try / catch

try {
  const result = await uploadVectors({ req, file, file_id });
} catch (error) {
  // Distinguish known_type/status errors from network errors
  if (error.message.includes('not supported')) {
    return res.status(415).json({ error: error.message });
  }
  if (error.message.includes('embedding failed')) {
    return res.status(502).json({ error: 'Embedding service error' });
  }
  // Generic network/unknown error
  return res.status(500).json({ error: 'Vector upload failed' });
}

Prevention

Check server logs for the detailed axios error logged by logAxiosError before this generic throw.
Verify RAG_API_URL connectivity and health before relying on vector uploads.
Consider preserving the original error type rather than wrapping, so callers can branch on cause.
Implement circuit breaker or retry logic for transient RAG API failures.

When it happens

Trigger: Any unhandled exception during uploadVectors: network failure reaching the RAG API (ECONNREFUSED, ETIMEDOUT), HTTP error status from the RAG API (4xx/5xx that throws from axios), or the known_type/status errors thrown inside the try block being re-caught here.

Common situations: The RAG API is unreachable (network error, DNS failure). Or the RAG API returns a 4xx/5xx HTTP error. Or an unsupported file type (error 116) or embedding failure (error 117) is thrown inside the try block and re-caught here, losing the original specific message because it wraps with error.message.

Related errors

AI-assisted analysis of danny-avila/LibreChat@5ff282f900 (2026-08-12). Data as JSON: /api/errors/6e18abca43fa4f9e. Report an issue: GitHub.