Implemented I can't complete challenge anymore

Hello,

When i click on the cobblestone challenge with 2 stack in my inventory and no timeout it say "You have not unlock this challenge yet!"

(I have uploaded 2 screens)

ps: the same problem happen for all challenge

 

Yea, no problem. All the challenges I've completed so far are no big deal anyway.

 

I can't do challenge as well. Same error.

 

hopefully this can be reset the soonest as I can't find a way to get leather... lol

 

You can use the Blood Magic alchemical chemistry set to turn rotten flesh into leather.

 

fyi, mob from my place seem doesn't drop any rotten flesh, not on killing with sword or grinder or fall, at least I dont see one from the day i start building mob spawner...

 

Try zombie pigmen