I don't know why but...
as you can see on the screenshot, the comparator clock is not working on any other comparators, somewhere else on the Minecraft map (from where the screenshot is) the clock worked, so ... I don't know how it happened.
The comparator that is pointing to the west, has an output of 0
the comparator that is pointing to the east, has an output of 1
I also replaced them, updated them, etc. but nothing changed.
The Map is running on a server (private) so not in singleplayer.