There are two most common reasons that sound is not played in Cubase.
The monitoring mode is set in the track itself.
Look at the indicator next to the track. To play the sound, the button must be inactive.
Audio output is programmatically prohibited.
It is necessary to follow the path “Studio” – “Audio connections” and make sure that the name of the output device is displayed in the “Outputs” tab in the “Audio Device” field.
If the status “Not connected” is displayed, click on this label and select the name of the output device driver.