That does seem to be the main issue, I’m afraid. I will update at our end so we can investigate why there might have been a drop in the link between the two servers on that day.
Might your participants be using a VPN to access the experiment?
I notice that the data file starts “undefined” because you have removed “participant” from the expInfo screen. If you don’t want to show your participants the word participant you could edit the code for the data file name