When a player trying to interact with blockling (press any button in blockling`s inventory) they just get kicked out of the game.

here`s the log: https://pastebin.com/J9cN1raX

i dont have much knowlege how to read log, so can you please say is it mod conflict or something more complicated?

also i tried to use it on singleplayer and it works different, in single i need to give flower to them in order to interact, but on server my friend just killed them in the wild and they dropped as items. then i just used item on floor and it spawned a blockling which dont need a flower, also it have no nametag above it (in singleplayer it has) but i still can give him items and cannot give flowers

Looks like this is for Minecraft 1.12.2. Is that right? If so 1.12.2 is no longer supported unfortunately.