I’d assumed it was that, because it confused me for a while, when I first loaded it up!
Digging deeper, what’s going wrong is that you’ve got a mountain range in the middle of the region, and cable can’t be laid over mountains or chasms. You do have a narrow gap in the ranges, but the gap isn’t wide enough to lay cable between them right now; the game really wants your network cables to be in accessible areas. (Right now, the game is demanding a 100m gap between a network cable and the nearest mountain… so a gap between two mountains needs to be more than 200m wide in order to admit a cable)
(I’m not claiming that that behaviour is the correct game behaviour, but that’s why the game is refusing to let you lay a cable from your initial area toward the coast)
So you have a few options. Network fiber can be laid over mountains and chasms. Alternately, a wifi node could be placed on your side of the mountains and would cover almost the entire other side of the mountain range.
In terms of game adjustments: Clearly the game needs to show that a network cable is obstructed the same way that it shows when a road is obstructed. I’m kind of startled that it already isn’t doing that. Probably needs a text explanation for the obstruction as well. Also, the “100m gap” thing is probably unnecessary; I should probably just remove it; it’s never going to be intuitive.