Try again, your chief is in there. To make sure you try everyone, go to your detail screen, select your oldest or youngest, then click out of the detail screen, that villager will be highlighted, try the robe. Go back to the detail screen, click over to the next villager, close detail screen, try robe. Do this until you cycle around to the first villager again. I believe before you get to the first one again, you'll find your new chief.
With 50 villagers, it's tough to make sure you try everyone.
Good luck!!
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CaliLilac