The problem is this:
I believe that shortly after the 1st release of Elite Dangerous, Frontier thought it would be great to have a companion app on the iPhone. So, they built one. Not very useful but still, that was a start. Now, this "companion" app needed data from the game. So, Frontier made some APIs (Application Programming Interface) accessible over the internet so that this companion app could pull your data and show you things like where you were docked, what the commodity prices were there, etc.
So, some ingenious people discovered this and started using those APIs to get data from the game. Since there was an API to check the price of commodities where you are docked, it was easy for the ingenious developers to get this data and then send it to eddn.
However, with each new major version of Elite Dangerous, the servers providing the APIs would go offline but they would come back after a few days.
Now, the companion app on the iPhone hasn't been upgraded in quite some time. Right now, with the current version of iOS, it crashes as soon as you launch it. With the release of Horizons, the servers providing those APIs have been offline and they are still offline. So, tools that rely on these APIs are SOL, they don't work because the servers they connect to to get the data are not responding.
That's the story. Now, it's everyone guess whether they will come back online or not. Frontier didn't do anything to prevent 3rd parties to use those APIs but it didn't encourage people to use them and didn't publicize it either...