Can't Connect to UltraNEXUS-HD WebNEXUS Web Interface Due to "Unsupported Protocol" Error

If the browser gives an "Unsupported protocol" or "ERR_SSL_VERSION_OR_CIPHER_MISMATCH" message, in most cases, this is due to old firmware in the UltraNEXUS-HD unit.

Check what version of firmware you are running.

  • You can check in WinLGX by going to the Tools menu and selecting Controller. The firmware will be listed after the serial number at the top of that window.
  • Or in the web interface Dashboard page, upper left area.

If it's not the latest version, you'll want to update your firmware to the latest firmware, which is version 21.07.29. That should correct the issue.

You can download the firmware file from our website at https://www.leightronix.com/downloads.


To firmware update, go to WinLGX – ToolsController. Click Browse to find the downloaded file, then Update.


Here's the link to our tutorial on how to firmware update: https://leightronixtraining.viebit.com/player.php?hash=Rcm2Sa7NA4oN