No Home Port in First U Boat Mission
 

I'm on the mission where you deliver the supplies to Taipei but after I dropped off the supplies they radioed I can patrol or return to base, but my home port disappeared off the map. Where is a friendly port for my U boat? I returned to Taipei but it won't let me finish the patrol.

Did you look at the map for a port with a slanted anchor? That's your new base. You may also have received a radio message advising of the base change, but not necessarily.