Changing IP addresses sometimes requires a reboot of the PC and a power cycle of the switch being used. Cache tables that map the IP to MAC addresses sometimes do not get updated quickly or at all depending on configurations. We recommend you power down the sensor. Power down the switch if possible, power down the PC. Then power the PC back up, then the switch, start Wireshark and set it to collect. Finally, power up the sensor.
By doing this, you should see the sensor announcing itself in the Wireshark data. Look for a device with a MAC address that starts with 60-76-88 (it may say Velodyne instead of these numbers). Then see which IP address is associated with this MAC address and use it to connect to the web page.
Set the sensor to the address you need and make sure you save the configuration before you leave the web page.
This should get the sensor up and running.
If this does not work get in touch with Velodyne for further assistance.