Hue Brightness feedback

[Firechief]

Admin,

I'm sorry, but as stated in my signature i am a novice at this.

So i've made a new "test" script and pasted the code in there, but nothing shows up.
I do get an error in the error log:

Code:

Hue Discovery Test 28.03.2023 11:22:58
Resident script:2: bad argument #1 to 'decode' (string expected, got nil)
stack traceback:
[C]: in function 'decode'

 So cleary i'm doing something wrong but i have no clue.