Vacuum shows E15 or a Wi-Fi/cloud icon (on smart models); app cannot connect to the vacuum.

Safety first: Connectivity issues do not usually pose electrical hazards, but avoid resetting while charging.

• 1. Restart vacuum: Power off the vacuum completely and remove the battery for 1 minute. Reinstall and power on.
• 2. Reset network settings: Follow the user manual to reset Wi-Fi/Bluetooth settings (often by holding a specific button combination for several seconds).
• 3. Check router: Ensure your router is on 2.4 GHz if required by the Grundig model and that the SSID and password are correct.
• 4. Re-pair in app: Remove the device from the Grundig app and add it again, following the pairing instructions.
• 5. If E15 persists: The wireless module PCB may be defective and will need replacement by a service center.