A USB turntable, I assume?
Make sure you’ve selected the USB device as your Audacity Recoding Device,
Check the recording volume slider which is now “hidden” under the recording meters.
Check the line/phono switch on the turntable. It may need to be set to “line”.
Check your Windows Permissions/Privacy Settings to make sure Audacity is allowed to use the turntable.
You can also check Listen To This Device to make sure Windows is getting a signal.