In the event Web Browser is non responsive, use the supplied COM Port connection to the rear of your HA3969.
Current firmware avoids all CLI such as SSH and Telnet. The best way to access your HA3969 GS without web browser is to connect the supplied console cable to the management port. The baud rate for the COM port is 38400.
Then check and see what IP addresses are picked up from there under TCP/IP>>>LAN0
In the event IP connection is lost or not possible, use Putty over a COM Port Connection with the supplied COM Port Cable. If a COM port is not available on your PC, use a USB to RS232 Serial DB9 Adapter Cable.
From Windows 10 for example, use the following settings in PUTTY for a serial connection.