1. Minecraft Java on Windows 11
2. Fresh install of MC 1.21
3. Fresh install of fabric-installer-1.0.1.exe
4. Added only these mod JARs:
5. chesttracker-2.4.6+1.21.jar | fabric-api-0.100.1+1.21.jar | Searchables-fabric-1.21-1.0.1.jar | YetAnotherConfigLib-3.5.0+1.21-fabric.jar

Connecting to a bukkit/spigot/paper server running 1.21, chesttracker is not persisting inventories between restarts of the game. latest.log includes repeats of:

[16:33:35] [Render thread/ERROR]: Error saving object
java.io.IOException: Error encoding to NBT DataResult.Error['Can't access registry ResourceKey[minecraft:root / minecraft:enchantment]

full latest.log shared here
only the hostname, port, and username have been changed for privacy

mc debug info in case it's useful

Fixed in 2.4.7

thank you so much for the quick fix! as a bonus, I was able to restore my pre-1.21 nbt file that had been marked as "corrupted" and it no longer gets punted by the mod. all is right in the world