schem_download will not work

[Leahcimkrob]

Unfortunately, downloading the schematic files no longer works under MC 1.20.6.
We don't get an error in the config, but we get a message in the chat saying that it is not a valid schematic file.
If we copy older schematics, it works, but not with newly created ones.
Paper: 1.20.6 build 147