1. Keep WiFi and Bluetooth on; 2. WiFi and Bluetooth connection distance is within 40 meters of accessibility, beyond which it will not be able to connect, or there are obstacles blocking the signal within the connection range, such as walls, houses, etc., it will also not be able to connect; 

1.If the camera's current Wi-Fi and Wi-Fi you want to switch can be connected at the same time, you can switch Wi-Fi directly by selecting Wi-Fi network in the settings interface. 2.When the camera is disconnected from the current WiFi, the app will display "Device disconnected". Click Troubleshoot to connect directly to another wireless network. Or remove the camera from the Tuya Smart and then connect the camera to the Wi-Fi you want to switch to. 

1.If the camera's current Wi-Fi and the Wi-Fi you want to switch can be connected at the same time, you can switch Wi-Fi directly by selecting Wi-Fi network in the settings interface. 2.When the camera is disconnected from the current WiFi, the app will show "Device disconnected". Click Troubleshoot to connect directly to a different wireless network. Or remove the camera from Tuya Smart and then connect the camera to the Wi-Fi you want to switch to. 

for Nikon G lens and Sony A7ii,please use this item, asin B07D5DV4PR,hope it helps. and if you need more help, please let us know. 

First remove and reset the device in the APP, then configure the network for the device again through the APP.