I've used Notty twice, once with Graff and once with a high ABV IPA. Both times I've had problems... I tried re-pitching with both without success. Try warming it up to 70*-72*F and agitating it to re-suspend the yeast. That didn't work for me but racking it onto a fully-attenuating yeast cake did.
Did you aerate well before pitching the yeast? I think it may have been part of my problem while using Notty.
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