harbor not placeable

[Max_turtle]

i can't place the harbor - only getting the image for placing buffs on Majors House

[Harlequin_1963]

same

[SnowBlizz]

Worked for me. Bought the Quest. Put it on Mayor's, completed the quest, placed the harbour building in only place it can go.

[Harlequin_1963]

resolved when i levelled.

[Graciethecat]

Had the same issue until I was reminded the harbor from the shop is to be placed on the MH, this will start the quest that rewards the harbor to be placed on the island. When completed in the correct order works great.
As a reminder, you may need to move a building/general if near the harbor dock location. These can returned after the harbor is placed.