Device Offline Troubleshooting

2.1 Identifying an Offline Device

2.2 Common Causes and Solutions

Issue 1: Offline After Restarting or Replacing the Router

Symptom: The device goes offline after the router is restarted, replaced, or its password is changed.

Cause: The Wi-Fi information saved on the device no longer matches the network.

Solution: Run Wi-Fi setup again.

Issue 2: Device Outside Wi-Fi Coverage

Symptom: The device is offline in one location but works normally after being moved.

Cause: Wi-Fi signal strength is too low (below -75 dBm).

Test with a phone:

1. Connect the phone to the same Wi-Fi network.
2. Stand where the device is located.
3. Check the Wi-Fi signal indicator on the phone.
4. Fewer than two bars indicates a weak signal.

Solution:

Adjust the device location:

1. Move the device closer to the router.
2. Avoid metal objects that block the signal.
3. Keep it away from microwave ovens, Bluetooth devices, and other interference sources.

Issue 3: IP Address Conflict

Symptom: The device goes offline intermittently or cannot obtain an IP address.

Cause: The IP address assigned by the router DHCP server conflicts with another device.

Solution:

Step 1: Restart the router
1. Unplug the router.
2. Wait 30 seconds.
3. Plug it back in.
4. Wait for the router to finish starting, about two minutes.

Step 2: Assign a static IP address (recommended)
1. Sign in to the router administration page.
2. Open DHCP Server > Static Address Assignment.
3. Find the TC002 device by its MAC address.
4. Assign a fixed IP address, such as 192.168.1.100.
5. Save the settings and restart TC002.

Step 3: Verify
1. After TC002 restarts, confirm that its IP address remains fixed.
2. Test whether the network connection is stable.

Issue 4: Too Many Devices Connected to the Router

Symptom: TC002 frequently goes offline when many smart devices are connected at home.

Cause: The number of connected devices exceeds the router capacity.

How to check:

1. Sign in to the router administration page.
2. Open the Connected Devices list.
3. Count the connected devices.
4. Compare the count with the router capacity:
   - Entry-level router: 10-15 devices
   - Mid-range router: 20-30 devices
   - High-end router: 50 or more devices

Solutions:

Option 1: Optimize router settings
1. Disconnect devices that are not in use.
2. Configure connection priority (QoS).
3. Give TC002 high priority.

Option 2: Upgrade the router
1. Choose a router with a higher device capacity.
2. A Wi-Fi 6 router is recommended.
3. Consider an enterprise-grade router when necessary.

Option 3: Separate network traffic
1. Use a dedicated router for smart devices.
2. Reserve the 2.4 GHz network for IoT devices.
3. Use the 5 GHz network for phones and computers.

Issue 6: DNS Resolution Failure

Symptom: TC002 shows that it is connected to Wi-Fi but cannot access cloud services.

Cause: The DNS server cannot resolve domain names.

How to check:

1. Sign in to the router administration page.
2. Check the DNS server settings.
3. Confirm that a working DNS server is configured:
   - Primary DNS: 114.114.114.114
   - Secondary DNS: 8.8.8.8 (Google)
   - Alternative: 1.1.1.1 (Cloudflare)

Solution:

Step 1: Change the router DNS settings
1. Sign in to the router administration page.
2. Open Network Settings > DNS Settings.
3. Set the DNS servers manually:
   Primary: 114.114.114.114
   Secondary: 8.8.8.8
4. Save the settings and restart the router.

Step 2: Verify
1. Restart TC002 and check its connection status.
2. Test a cloud feature, such as remote control.

Issue 7: Firewall or Security Software Blocking the Connection

Symptom: TC002 is accessible on the local network but cannot connect to cloud services, so calendar and social-media data are unavailable.

Cause: A router firewall or security application is blocking device communication.

Solution:

Step 1: Check the router firewall
1. Sign in to the router administration page.
2. Open Security Settings or Firewall.
3. Temporarily disable the firewall for testing.
4. If the connection works, add TC002 to the allowlist.

Step 2: Check required ports
Make sure these ports are not blocked:
- TCP 80 (HTTP)
- TCP 443 (HTTPS)
- TCP 8883 (MQTT)
- UDP 123 (NTP time synchronization)

Step 3: Disable parental controls for TC002
1. Open Parental Controls or Access Control.
2. Check whether TC002 is restricted.
3. Remove the restriction or add an exception.

2.3 Offline Troubleshooting Flow

┌─────────────────────────────────────────────────────────────┐
│                 Device Offline Troubleshooting              │
└─────────────────────────────────────────────────────────────┘

Step 1: Confirm the offline status
    ↓
┌─────────────────┐
│ App shows       │
│ Offline?        │
└────────┬────────┘
         │
    ┌────┴────┐
    │         │
   Yes        No
    │         │
    ↓         ↓
 Step 2    Check the app network connection

Step 2: Check the device
    ↓
┌─────────────────┐
│ Is the screen   │
│ on?             │
└────────┬────────┘
         │
    ┌────┴────┐
    │         │
   Yes        No
    │         │
    ↓         ↓
 Step 3    Check device power

Step 3: Check the network
    ↓
┌─────────────────┐
│ Is the router   │
│ working?        │
└────────┬────────┘
         │
    ┌────┴────┐
    │         │
   Yes        No
    │         │
    ↓         ↓
 Step 4    Restart the router

Step 4: Check signal strength
    ↓
┌─────────────────┐
│ Signal above    │
│ -75 dBm?        │
└────────┬────────┘
         │
    ┌────┴────┐
    │         │
   Yes        No
    │         │
    ↓         ↓
 Step 5    Improve Wi-Fi coverage

Step 5: Run Wi-Fi setup again
    ↓
1. Hold the Reset button for five seconds.
2. Scan the setup QR code.
3. Enter the Wi-Fi information.
4. Wait for the connection to finish.
    ↓
┌─────────────────┐
│ Connected?      │
└────────┬────────┘
         │
    ┌────┴────┐
    │         │
   Yes        No
    │         │
    ↓         ↓
  Done     Contact technical support

Environment Recommendations

Recommended:
- Place the router near the center of the home.
- Keep a clear line of sight between TC002 and the router.
- Use a dedicated 2.4 GHz network for IoT devices.
- Update the router firmware regularly.

Avoid:
- Placing the router in a corner or cabinet.
- Placing TC002 near microwave ovens, Bluetooth speakers, or other interference sources.
- Combining both bands when it causes frequent band switching.
- Leaving the router running indefinitely without an occasional restart.