you guys find any problem with harbor?

I want to share my problem lately. So I capture Athens, and later I annex it, it is build siding by the coast/sea, and I want to make a trade route between Athens and my capital to get more income. When it already build still the trade route was not there, then I wait for a while because when I build the harbor to my other city the trade route establish 1 turn after I finish my harbor. And many turns already pass, still the trade just not there.

What happen here? is there anybody share the same problem like me? is it a bug?

You have to be able to physically see a water path from your city to Athens. An inland ocean, for example, cannot connect to the ocean that's outside of the landmass.

thank you Tachii now I know what happen