My furnaces are not working, when I click on empty "output" slot it says : [SocketableItems] This item has been disabled. But only thing I found in configuration is Use_Stack_Amounts_In_Furnace: true and that is set to true. I'm sorry if it is any common knowledge but I'm kinda noob in this stuff .. :) Is there any way to set furnaces on ?

The only time that message would appear is if you are setting an item to 0 in items.yml. Can you post your items.yml config?

allWorlds:
default:
MIN: 127
MAX: 127
testPlayer:
MIN: 127
MAX: 127
testGroup:
MIN: 127
MAX: 127
chest:
MIN: 64
MAX: 64
testWorld:
default:
MIN: 127
MAX: 127

So is there any solution or do I have to shut off the plugin ?

Please test this on v1.0 and let me know if it is still happening.