langflow-ai/langflow · error · Error

Failed to download files: ${response.statusText}

Error message

Failed to download files: ${response.statusText}

What it means

500 returned when the user switches auth away from OAuth (stopping MCP Composer) and get_project_streamable_http_url() comes back empty, so the response cannot include a direct connection URL. This indicates the direct project MCP server is not addressable — typically because host/port settings are unset or the URL builder failed.

Source

Thrown at src/frontend/src/controllers/API/queries/file-management/use-get-download-files.ts:46

          credentials: getFetchCredentials(),
        },
      );
    } else {
      response = await fetch(
        `${getURL("FILE_MANAGEMENT", { mode: "batch/" }, true)}`,
        {
          method: "POST",
          body: JSON.stringify(params.ids),
          headers: {
            "Content-Type": "application/json",
            Accept: "application/x-zip-compressed",
          },
          credentials: getFetchCredentials(),
        },
      );
    }
    if (!response.ok) {
      throw new Error(`Failed to download files: ${response.statusText}`);
    }

    const blob = await response.blob();
    const url = URL.createObjectURL(blob);

    const filename = parseContentDispositionFilename(
      response.headers.get("Content-Disposition"),
      "files.zip",
    );

    const link = document.createElement("a");
    link.href = url;
    link.setAttribute("download", filename);
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);

    URL.revokeObjectURL(url);

View on GitHub (pinned to 976ec789d2)

Solutions

1. Set host and port in Langflow settings (LANGFLOW_HOST / LANGFLOW_PORT or equivalent) and retry the PATCH.
2. Inspect get_project_streamable_http_url in the logs to see which input was empty.
3. For proxy deployments, configure the externally advertised host, not just the bind address.

settings = await client.get_settings()
host, port = settings.host, settings.port
if not host or not port:
    raise EnvironmentError("LANGFLOW host/port unset; cannot build direct MCP URLs")

When it happens

Trigger: PATCH project MCP settings changing auth_type from oauth to apikey/none with composer stopping, while settings.host or settings.port is empty (or the URL build returns falsy).

Common situations: Running Langflow behind a reverse proxy with LANGFLOW_HOST/PORT unset; container deployments where the bind host is not the externally reachable host; partially configured .env.

Related errors

• Failed to reload bundle
• Failed to delete MCP Server
• Invalid file type
• HTTP error! status: ${response.status}
• Failed to load models. Please check your provider credential

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/c34a12fc6940fe5d. Report an issue: GitHub.