rotator suddenly will not initialise

[Fred VE3PIE]

I installed a new extended webswitch with 1216S adapter cable. I have a Yaesu G-2800DXA rotator, and am using the DCU-1 protocol at 4800 baud. The webswitch has software version 3.3, hardware 2, bootloader 1.10.
It was working perfectly, but now when I press the power button it says "initialisation in progress" and then "rotator not initialised", and remains disabled.
I checked the connections of the 1216S adapter to the board, and it is ok.
There is a green LED next to the USB port that is constantly flashing on and off, and I don't know if this is normal.
Can anyone help ?
thanks, Fred VE3PIE

[Jan (Microbit)]

It seems something has happened which prevents the WS from communicating with the rotator as the WS fails to initialise it. Did it stop working suddenly without any changes made to the system?

The green LED should flash slowly, that is the "heartbeat" of the WS