Inter City Trade is Not Working properly

[Smoss 0]

I am encountering a problem where I can no longer trade most resources between cities. Until recently my Main city served as the only power producing center in my region, but now for some reason I can't transmit power across multiple cities so I had to abandon several of my cities. I am also encountering a problem where I can no longer trade garbage to my main city, and it was also the only landfill in the region, so most of my cities now no longer work at all. All of my cities are connected with roads and power lines so this isn't the problem. Anyone know what I can do.