How to use the Catalog API properly?

What I am trying to do is getting all the accessories and hopefully other asset types. When I tried to get the webpages, it didn't work. Do I have to do this in another programming language, like JavaScript?

local url = "https://search.roblox.com/catalog/json?Category=11" --// This URL will show page of accesssories

print(game.HttpService:GetAsync(url)) --// Trust check failed

print(game.HttpService:JSONDecode(url)) --// Can't parse JSON

The comments on each line will show you the error message or the description.