What to do if the Xiaomi Smart Camera C300 cannot connect to a Wi-Fi network?

The APP displays that the device is offline, please refer to the following steps: 
1. Check whether the Xiaomi Smart Camera C300 is unplugged or disconnected from the power supply;
2. Check whether the router is working properly, whether the router is powered on, and whether the Wi-Fi name and password of the router are changed;
If steps 1 and 2 above are confirmed correct, please troubleshoot the following information:
1. Check if Wi-Fi is 2.4Ghz;
2. Ensure the Wi-Fi is in good condition and the device is within the Wi-Fi coverage;
3. The mobile phone is connected to the Internet normally, and the camera is also close to the Wi-Fi router and the blue light is still blinking. Please try to turn off the power of the Xiaomi Smart Camera C300 and restart it;
4. The above steps operation still can not be solved, please restore the device to the factory settings.