Noise reduction not workig.

Interface moukey MSc1 on Windows 10.
After I record a vocal track , I grab a small patch of track after that. However , when I try to get a noise profile , it always says "profile to short ". It’s in my effects list and enabled , just can’t get a profile. Appreciate any help.

Which version of Audacity? (look in “Help menu > About Audacity”)

How long is the selection?