Well... a long time ago, on a very advanced space station, we found out that the technology there could detect and hack the psychic network.

And more recently, something else shut down the network and Liminal Space for half a jaunt. A...

I'm not sure how to describe it. A monster trying to get into that world was involved, but I'm not sure if it shut things down, or if the Trumps did, to keep it out, or if something else happened.