Problems using API Items Adder

SrMaster

the id of the block I want to set the error it sends is

CustomBlock customBlock = CustomBlock.getInstance(args[0]);

LOG https://paste.helpch.at/aduwicaqip.rb

SrMaster

From what I understand the id would be

LoneDev

Please do not share screenshots of configurations, you are a developer you should know that.
Anyway probably your item is not a custom block that's why you cannot get it. If you get it using CustomItem.getInstance it will work since the item exists.
You have to add the block configuration part.
Follow the wiki. https://itemsadder.devs.beer/plugin-usage/adding-content/block

Another reason could be that the block item didn't load for some reason.
It's impossible to help you more than that.