FlowiseAI frontend not starting (blank UI) when installed via Proxmox CT community script (Node 22.x, Debian 12)

[mazixs]

✅ Have you read and understood the above guidelines?

yes

📜 What is the name of the script you are using?

FlowiseAI

📂 What was the exact command used to execute the script?

bash -c "$(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main/ct/flowiseai.sh)"

⚙️ What settings are you using?

• Default Settings
• Advanced Settings

🖥️ Which Linux distribution are you using?

Debian 12

📝 Provide a clear and concise description of the issue.

After installing FlowiseAI via the recommended script on a fresh Debian 12 server, the frontend does not load: browser shows a blank page, and only a root div is present in the HTML. No UI or React components are rendered. There are no visible errors in browser console or logs. The issue persisted after reinstalling and restarting the service.

🔄 Steps to reproduce the issue.

1. Wait for the installation to complete.

2. Start FlowiseAI (systemd service starts automatically).

3. Open http://:3000 in a browser.

4. See a blank page and empty frontend folder.

❌ Paste the full error output (if available).

[INFO]: Starting Flowise...
[INFO]: 📦 [server]: Data Source initialized successfully
[INFO]: ⚡️ [server]: Flowise Server is listening at :3000

🖼️ Additional context (optional).

The community script for Proxmox always installs the latest Node.js (currently 22.x).

FlowiseAI is only compatible with Node.js 18.x or 20.x LTS for frontend build (see #4552, #3294).

After manually switching the Node.js version to 20.x using nvm, reinstalling flowise globally, and adjusting the systemd service, the frontend UI loads and works correctly.

Suggested fix:
Add a Node.js version check to the install script, or enforce the use of a supported Node.js version (18.x or 20.x) for FlowiseAI installation.