Diagnosis
The hub itself is online (white light), but your Zigbee mesh network is unstable. Individual devices are losing their connection to the hub or to other devices that relay their signal.
How to Fix It
The M2's internal antenna isn't super powerful. You need to build a robust mesh. Ensure you have several mains-powered Zigbee devices (like smart plugs or light switches) spread throughout your home. These act as repeaters. Avoid putting battery-powered sensors (like door sensors) far from the hub or a repeater. In the app, check the signal strength (RSSI) for devices that drop; if it's poor, physically move either the device or add a repeater closer.
If That Didn't Work
Signal interference is a prime suspect. The M2 uses the 2.4GHz Zigbee band, which is crowded. Keep it away from your Wi-Fi router, microwaves, and cordless phones. If your Wi-Fi router is nearby, try changing its 2.4GHz channel to 1 or 11, leaving the middle channels (6) more clear for Zigbee.
Heads Up
Some USB 3.0 hubs, external hard drives, or poorly shielded laptop chargers can emit massive interference in the 2.4GHz spectrum. If your M2 is sitting right next to one on a desk, that's likely your culprit.