Edit > Device Setup. Reset your sample rate.
Could be that Dorico’s set it at 96k hertz and another program has changed it to 48k, for instance.
For most purposes - particularly within an application where everything’s sampled or modelled - 44k or 48k will do just fine. Dorico can work at anything your audio device can support; it just doesn’t know if another program’s taken control of that audio device and changed the sample rate behind the scenes.