Thank you so much! I found the problem (it was the Photosynthesis mod, which I didn't think would be a problem, but it makes sense since it hasn't been updated in a while).1) Deactivate all but one mod.
2) Start a new game.
3) Open the console and enter "survey".
4) You should get lots of first contact chains right away. If not, the active mod is the culprit. Otherwise, close the game and try it again with another mod enbaled.