Portland is 9 hours behind Copenhagen
Best overlap: 5:00 PM to 6:00 PM in Copenhagen is 8:00 AM to 9:00 AM in Portland.
Copenhagen and Portland overlap from 5:00 PM to 6:00 PM (Copenhagen) to the equivalent 8:00 AM to 9:00 AM in Portland — that's your meeting window. The shared window is only 1 hour — treat 5:00 PM in Copenhagen (8:00 AM in Portland) as the one fixed point and plan everything else around it.