u/Forward-Can-3575

So here's the thing, I'm relatively new to the game and I've probably got maybe 10 hours in. I'm trying to unlock iron excavation by building an iron mine on the small island just north of me from where you first started out on the campaign. When I try to build the mine, it says route to harbor/warehouse blocked. I've tried to run a road from the new trade Post that I have built right there on the shoreline and it doesn't do anything. What am I doing wrong cuz it's driving me crazy?