Device networking issues

When adding a Zigbee sub-device, the message "Unauthorized, unable to add" appears, and the gateway cannot find the device. What should I do?

How to troubleshoot if Wi-Fi device fails to connect successfully?

What is the specification of the Wi-Fi password when adding devices?

Why the device failed to connect (Bluetooth)?

How to add device in App for Internet connection(Zigbee)?

What should I do when my device fails to connect to the network?

My device needs to be configured for the network. How do I reset the device?

Can Wi-Fi and Bluetooth combo devices be added at the same time with two communication methods?

How can devices be connected without Wi-Fi and only mobile hot spots?

Does adding sub-devices under the Zigbee gateway need to be on a 2.4GHz network?