1. This problem may be caused by physical reasons such as power failure or network cable loose. Please make sure the power supply and cables are in good working conditions, and replace them properly if necessary.
2. Maybe the problem of the OpenVPN connection failed, please check if the OpenVPN parameters are configured correctly.
3. Maybe the problem of the network is unstable and a large number of packets are lost, please make sure the network is stable.
4. This may be caused by the gateway router port(OpenVPN establishment port) is not released, please contact your local IT.