External Sync no longer recognises external MTC link

Hi Folks,
After several successful years syncing up my Roland VS1680 with Cubase 11, it suddenly stopped syncing. The Activate External Sync is checked off, the ASIO driver is set correctly on the USB interface, I have not changed any of the MIDI or Sync parameters on the Roland, and as you can see from the screenshots, I think I’ve set up the External Sync correctly. But now it does not sync with the Roland MTC signals. The screenshot shows the Roland with the MODX shut off, but that should not make a difference. When the MODX synth is turned on, the Roland unit does not show up, but the syncing does not work, where it did just a couple of days ago. Suggestions graciously appreciated.