Can't Replace A World From Your Worlds List To The Realm

I've had tried to use my expired realm I have to transport a world to another device to put a resource pack on, then to get it back to my switch. But when I try to replace the world over and over again, it doesn't work and said "Failed to find a place to upload your world. Maybe check your internet connection?" and yes I have tried 3 networks and none of them work please fix this and I hope I can upload the texture pack to the realm.