You need to go into singleplayer and remove anything you have in the obelisk. Check all 3 tabs in the obelisk. If there is nothing in there or there is something that is stuck that you cant remove like a specimen implant you need to delete your singleplayer data. To do that, in the screen before you start singleplayer, the host/local screen, there is a button at the top to delete all your data. This is not the same as deleting each map save it has to be the "all" button.