I don't see anything, but I might not be looking in the right place.
It's in the server window or nowhere.
So if there is nothing, the server does not even get
the request properly.
I looked through all the tabs of the dev console but didn't see anything pertaining to ymarks. Again, though, I might be looking in the wrong place.
Usually, the second tab with everything "enabled" and no filter set should be enough ...
Yes, as above, I'm running Firefox v61.0.2.
Argh. Sorry, I started typing without reading properly.
I will look into it in 28 hours!