Atlantic Cloud Connectivity Desynchronization

Atlantic app shows thermostat offline even though local control works.

Possible Causes

Stale cloud session, Changed router or ISP, Double NAT or VPN on home network, Outdated thermostat firmware

Safety first: No electrical work required.

Step 1 – Log out/in: Log out of the Atlantic app and log back in to refresh the cloud session.
Step 2 – Reboot router and thermostat: Power cycle both devices to force new connections.
Step 3 – Check network topology: Avoid double NAT (router behind another router) or VPNs that may block inbound/outbound connections.
Step 4 – Firmware update: When the thermostat briefly appears online, trigger a firmware update if available.

Very Easy 1/5