Hi there!
Firstly, try pinging '
smartkit-toolbox-flag.huawei.com', or access the following website in the maintenance client:
If the ping is OK or the website is accessible, it means the network is OK. Maybe there is a proxy between the maintenance client and the network; try configuring the same proxy in SmartKit.
If the ping is not OK or the website not accessible, then you need to check the network, such as checking the firewall setting.