Weird multiplayer problem

I'm having a pretty weird problem where I can invade other people's worlds, but can't have people come to my world. Whenever I use the finger remedy, it never shows any summon signs, even if I'm right outside of a major boss where there will 100% be summon signs. Also, whenever I place down my summon sign, I literally never get summoned. How do I fix this? I want to play co-op multilayer.