Thanks. Can you invade another port in Turkey on the Black Sea or am I just stuck until I capture Gallipoli.

<t> I am new to the game but having a good time. Is there a trick to invading an enemy port/beachhead? I control the particular sea (Black Sea), have transports, and used an HQ command. All the units come up as having amphibious, but I click on a unit, then amphibious and the enemy port but it just ...