--- title: "Set Up RTX Spark as Your Always-On AI Hub — Troubleshooting" canonical: "https://build.nvidia.com/playbooks/ai-hub/troubleshooting.md" --- # Troubleshooting Find your symptom in the tables below. Step numbers refer to the **Remote Access** tab unless another tab is named. ## RTX Spark or a service is offline | Symptom | Cause | Fix | | :--- | :--- | :--- | | RTX Spark stops responding after it has been idle | It went to sleep or hibernated. | Set the sleep and hibernate timeouts to **Never** (Step 2). | | Remote desktop cannot find RTX Spark | RTX Spark is off or offline, or its name is not found on the network. | Check that RTX Spark is on and connected to your network. Try its IP address in place of its name. Away from home, check that Tailscale is connected on both devices. | | Your agent does not answer | The agent app is not running on RTX Spark. | Connect with remote desktop and open the agent app (**Agents** tab, Step 2). | | An app cannot reach the inference server | The model server is not running on RTX Spark. | With PAIR, check that both devices show as connected and that the engine is running. With Tailscale, run `tailscale serve status` on RTX Spark and check that the llama.cpp server is still running. | | ComfyUI does not open from another PC | Comfy Desktop is closed, or ComfyUI is not accepting connections from other PCs. | Open Comfy Desktop on RTX Spark. Check that `--listen` is in **Startup Arguments** and that Windows Firewall allows ComfyUI on private networks (**Creators** tab, Step 2). | ## After a restart RTX Spark restarts for some Windows updates. Remote desktop comes back on its own. Most apps start only after someone signs in to Windows, so sign in through remote desktop first, then check what you use. | What you use | After a restart | How to check or restart it | | :--- | :--- | :--- | | Tailscale | Reconnects on its own when **Run unattended** is on. | Run `tailscale ping rtx-spark` on another device. If it fails, sign in through remote desktop on your home network and turn on **Run unattended** (Step 4). | | Agent | Starts after you sign in, if you set it to start at sign-in. | Send the agent a message. If it does not answer, open the agent app on RTX Spark (**Agents** tab, Step 2). | | PAIR | Check it after you sign in. | Open PAIR on RTX Spark and check that the engine is running and the model is listed. | | llama.cpp server | Does not start on its own. | Run the server command again on RTX Spark (**Inference** tab, Route B). The Tailscale address is shared again on its own. | | ComfyUI | Does not start on its own. | Open Comfy Desktop on RTX Spark and start the instance (**Creators** tab, Step 4). | ## Sign-in and access | Symptom | Cause | Fix | | :--- | :--- | :--- | | Microsoft Remote Desktop rejects your sign-in | Remote Desktop accepts your account password, not a PIN or other Windows Hello sign-in. | Sign in with your Windows account password. If your account has no password, add one first. | | Remote desktop works at home but not away from home | Microsoft Remote Desktop reaches RTX Spark only on your home network unless you add Tailscale. | Set up Tailscale (Step 4) and connect to RTX Spark’s Tailscale name. | | RTX Spark drops off your Tailscale network after several months | Its Tailscale sign-in expired. | Sign in to Tailscale again on RTX Spark, then select **Disable key expiry** in the admin console (Step 4). | | A device cannot open RTX Spark’s Tailscale address | The device is not on your Tailscale network, or your access controls block it. | Sign in to Tailscale on that device with the same account. Review your [Tailscale access controls](https://tailscale.com/docs/features/access-control). | | The agent app on another PC is refused, or asks you to sign in again | The sign-in details or token set on RTX Spark are wrong, changed, or expired. | Sign in again with the details you set on RTX Spark. See your agent’s guide (**Agents** tab, Step 3). | | ComfyUI Manager will not install custom nodes | ComfyUI Manager blocks installs while ComfyUI accepts connections from other PCs. | In the instance’s **Manage** panel, set **Manager Network Mode** to **Personal cloud**. See [Manage instances](https://docs.comfy.org/installation/desktop/usage/manage) in the Comfy Desktop documentation. | ## Endpoints and models | Symptom | Cause | Fix | | :--- | :--- | :--- | | An app reports a connection error or “not found” | The server URL is wrong. | Check that the URL ends in `/v1`. With PAIR, copy the URL from **Endpoints** in PAIR on the PC where the app runs. With Tailscale, use the `https://` address from `tailscale serve status`, not `127.0.0.1:9931`. | | An app connects but shows no models, or reports that the model is not found | The model is not available on RTX Spark, or the model name in the app does not match. | Run `curl.exe /models`, where `` ends in `/v1`, and enter the exact model ID it returns. With PAIR, add the model on RTX Spark (Step 4 of Set Up the PAIR App). | | The Tailscale address works at home but not away from home | Tailscale is disconnected on your laptop. | Connect Tailscale on your laptop, then run `tailscale ping rtx-spark`. | ## Apps and devices that cannot connect | Symptom | Cause | Fix | | :--- | :--- | :--- | | An app has no setting for a custom endpoint | The app does not support OpenAI-compatible endpoints. | Use an agent or app that lets you add a custom endpoint (**Inference** tab, Step 3). | | A device cannot run PAIR | PAIR runs on Windows, Linux, and macOS computers. | Use the Tailscale route, which works with any device that can run Tailscale (**Inference** tab, Route B). | | Microsoft Remote Desktop cannot be turned on | Windows Home cannot host Microsoft Remote Desktop. | Use Chrome Remote Desktop or RealVNC Connect (Step 3). | | Black or low-resolution screen after you unplug the monitor | Chrome Remote Desktop and RealVNC show RTX Spark’s own display. | Connect a dummy display plug to RTX Spark (Step 5), leave a monitor connected, or use Microsoft Remote Desktop. | | The remote desktop picture is laggy | Microsoft Remote Desktop is limited to 30 FPS by default, or the network is slow. | Raise the limit to 60 FPS with [Microsoft’s guide](https://learn.microsoft.com/en-us/troubleshoot/windows-server/remote/frame-rate-limited-to-30-fps). Use a wired network connection on both PCs. |