hi - have same problem (elf) with citadel upgrade (2nd wall) - i start 2 days ago and 2nd wall surround my city by 3/4, have all OP reinforced, some lonely towers near, only 2 gates (1st wall have 3) - i have resources (stone) and no button for construction/pause wall. If u can give me an advice will be great - many thanks and sorry for my English.
I attach 5 screen shots (i can't more than 5).2nd wall end1.jpg
2nd wall end2.jpg
main gate on 1st, 2nd no gate.jpg
no 2nd wall.jpg