First, don't put target_ply in a table bracket.
The player is already a table object.
Second, you do have and are inserting a Steam API key where it says 'insert' one, right?
Third, and quite a large 'this won't work' ... you're using ply:SteamID64.
You'd either want affected_plys (why the S, you're using the single ULib player object command in your command setup) or target_ply.
Fourth, those are all in my quick review, see where it takes you.
I'd have to write my own code to teach myself http.Fetch from there.