A few things to check:
1. Make sure that you can see the display output from NextD on your TV first
2. If you have an AV Receiver box between the NextD Player and your TV, make sure that it is turned on and configured properly to pass the audio signals from NextD's HDMI output to your external speakers.
3. If you have an HDMI port splitter between the NextD Player and your TV, please try removing it first to see if it blocks the HDMI signals.
4. If your NextD Player is directly connected to the TV via HDMI, make sure that your TV is configured to receive audio signals from the same HDMI port.
5. Sometimes, devices connected to TV's other HDMI ports can interfere with the HDMI port used for NextD. Please also try disconnecting all other HDMI ports to see if this is the case.
6. [NextD N2] If you want the audio output through the SPDIF port, please make sure to use a 3.5mm digital coaxial SPDIF cable and adjust the "Digital Sound" settings on NextD to change it to SPDIF.
If none of the above works, please contact the NextD support team for further assistance. All NextD products come with 1 year manufacturer's warranty. We will send you a free replacement unit whenever it is needed.