the app says 'device offline' but the thermostat itself is on and working fine on the wall.

Diagnosis

The "Device Offline" status on the Vine TJ-610 indicates a breakdown in the communication chain between the thermostat's internal WiFi module and the Vine cloud servers, despite the local hardware remaining functional. Because the thermostat continues to regulate temperature on the wall, the primary control board is powered and operational, but the network handshake has failed. This is typically caused by a DHCP lease expiration, a signal drop-out that failed to auto-reconnect, or a conflict following a router firmware update that changed the channel or security protocol. To confirm this is a network issue and not a hardware failure, check the WiFi icon on the TJ-610 display. If the icon is blinking or has a small "X" through it, the device has lost its local IP assignment. If the icon appears solid but the app still says offline, the issue lies in the "heartbeat" signal between your home router and the Vine remote servers, often caused by a firewall block or a DNS resolution error within the router's settings.

How to Fix It

Follow these steps precisely to re-establish the cloud handshake and clear the cache on both the hardware and the application:

1. Perform a power cycle on your network hardware. Unplug your router and modem from the wall outlet, wait exactly 60 seconds, and plug them back in. Wait until the internet light is solid green before proceeding.
2. On the TJ-610 wall unit, press the Menu button. Navigate to the Wi-Fi settings submenu using the arrow keys.
3. Select Disconnect or Forget Network to clear the existing cached credentials. This forces the device to request a new IP address from the router.
4. Select Connect and scan for your 2.4GHz SSID. Enter your WiFi password carefully; remember that the TJ-610 is case-sensitive and does not support 5GHz bands.
5. Once the screen confirms "Connected," go to your smartphone. Force-close the Vine app by swiping it away from your active apps list (don't just minimize it).
6. Relaunch the app and refresh the dashboard by pulling down on the main screen. The status should transition from "Offline" to "Online" within 30 seconds.

If That Didn't Work

• Perform a Hard Hardware Reset: Gently pull the TJ-610 faceplate straight off the wall mounting bracket. Leave it disconnected for 60 seconds to drain the internal capacitors. Slide it back onto the pins firmly. This forces the WiFi chip to reboot independently of the temperature control logic.
• Check Band Steering: If you have a "Smart" router that combines 2.4GHz and 5GHz into one name, the TJ-610 often gets kicked offline. Log into your router settings and create a separate guest network specifically for 2.4GHz devices, then connect the thermostat to that dedicated SSID.
• Assign a Static IP: Access your router's DHCP reservation table. Find the MAC address of the TJ-610 and assign it a static IP address. This prevents the "Device Offline" error that occurs when the router rotates IP addresses and the Vine cloud loses track of the device.
• Clear App Cache: On Android devices, go to Settings > Apps > Vine > Storage and select "Clear Cache." On iOS, delete the Vine app entirely and reinstall it from the App Store to clear corrupted session tokens.

Heads Up

• The Vine TJ-610 strictly requires a 2.4GHz connection. If you upgrade your router to a WiFi 6 model, ensure "Legacy Mode" or 2.4GHz compatibility is enabled, or the device will perpetually show as offline.
• Avoid placing large metal objects or mirrors directly between the thermostat and your router, as this can cause intermittent signal attenuation leading to random offline statuses.
• If you change your WiFi password, you must manually update it on the wall unit first; the app cannot push a new password to a device that is already offline.
• Check for server-side outages via the Vine community forums if multiple devices in your home are showing offline simultaneously.