Hi, friend!
B818-263 is a consumer product.
Since I am not sure about your specific problem, you can log in to the web of the device according to the information on the device nameplate and check the network status of the device on the web of the device . If the uplink rate is low, you can try to recover by restarting and resetting the device If you still cannot restore the device's upstream network, because your network is maintained by an ISP, you can contact your ISP for a corresponding solution.
Thanks!