Advancements can't parse on server

every other day our advancements on the server, that we own by a hosting service, gets reset.
now, this isn't really a big deal or game breaking in any way, but it would be nice to keep track of them and that they would work like they intend to.

what I'll try is making a backup of the server, delete the advancements files for the players and upload new and fresh server files.

I've uploaded a piece of the console where the error is descripted in detail for the most part.
I'll keep the backed up files in case they'll come to use!