my robot just randomly disconnects from wifi every day and i have to reboot it to get it back on the app

Diagnosis

The Dreame L40 Ultra utilizes a network chip that is highly sensitive to "band steering," a feature in modern Mesh WiFi systems and dual-band routers where the router attempts to force devices onto the 5GHz band to clear congestion. Because the L40 Ultra is strictly a 2.4GHz device, it cannot communicate on 5GHz; when the router attempts to "steer" the robot, the connection is severed. Once the robot loses this handshake, it often enters a deep-sleep network state to conserve battery, failing to trigger the automatic reconnection protocol. Furthermore, this issue is frequently caused by "DHCP Lease Expiration." If your router is set to a short lease time (e.g., 24 hours), the L40 Ultra may fail to request a new IP address correctly upon waking from its standby mode. This results in the "Device Offline" status in the Dreamehome app, which persists until a hard reboot forces the network interface to restart and request a fresh IP assignment from the router.

How to Fix It

To permanently resolve the connectivity drops, you must isolate the robot's connection and stabilize its network identity. Follow these precise steps:

1. Access your router's admin panel via your web browser (usually 192.168.1.1 or 192.168.0.1).
2. Navigate to Wireless Settings and disable "Smart Connect" or "Band Steering."
3. Rename your 5GHz band to something distinct (e.g., "HomeWiFi_5G") and keep the 2.4GHz band as "HomeWiFi." This ensures the L40 Ultra never attempts to handshake with the wrong frequency.
4. Go to the LAN/DHCP settings menu. Locate the "Address Reservation" or "Static IP" section.
5. Find the L40 Ultra in the list of connected devices (it usually appears as "dreame-vacuum" or a string of MAC addresses).
6. Assign a permanent Static IP to the robot's MAC address. This prevents the robot from disconnecting when the DHCP lease expires.
7. Change the 2.4GHz channel width from "Auto" or "40MHz" to a fixed 20MHz. This increases signal stability and penetration through walls, reducing random drops.
8. Restart the L40 Ultra by holding the power button for 10 seconds and then reconnect it to the newly renamed 2.4GHz SSID via the app.

If That Didn't Work

• Disable WPA3 Security: The L40 Ultra can struggle with the latest WPA3 encryption protocols. Change your router's security setting to WPA2-PSK (AES). This is the gold standard for IoT device compatibility and often stops the daily disconnects.
• Adjust Firewall/DNS Settings: Some aggressive router firewalls block the specific ports Dreame uses to ping its cloud servers. Change your router's DNS settings to Google DNS (Primary: 8.8.8.8, Secondary: 8.8.4.4) to ensure the robot can always find the Dreamehome server.
• Relocate the Base Station: Ensure the L40 Ultra dock is not placed directly against a mirrored wall or a large metal appliance (like a refrigerator). These create "multipath interference" where the signal bounces, causing the robot to lose its connection as it returns to the dock.
• Update Firmware via App: Check for a pending firmware update in the app settings. Dreame frequently releases "Network Stability" patches that specifically address the wake-from-sleep reconnection bug.

Heads Up

• Avoid using special characters or spaces in your WiFi SSID and password; the L40 Ultra's network stack prefers alphanumeric characters.
• If you use a Mesh system (like Eero or Google Nest), try disabling the "Client Steering" feature specifically for the robot's MAC address.
• Keep the robot's charging contacts clean; if the robot has a momentary power dip while docking, it can trigger a network reset.
• Do not place the dock in a "dead zone" where your phone has only one bar of signal; the robot requires a stronger RSSI (Received Signal Strength Indicator) than a smartphone to maintain a stable cloud link.