Question: how to get edz obelisk to work?
Answer: Wait. That's it, just wait by the obelisk and the button prompt may show up after about five minutes.
Fast travel to another area, then fast travel back to the obelisk. ( Have to say this did not work for me)
Leave the planet, go in to orbit, return back to the EDZ, then head to the obelisk.
Clear your cache.