In some cases, the switch may not pass audio through the 3.5mm or Toslink ports.
Double-check that the volume of the device receiving the 3.5mm or Toslink audio output is loud enough to hear any audio being play. If the HDMI device providing the video and audio to the switch has adjustable volume, make sure that volume is also turned up.
Try removing all connected cables, including all HDMI, 3.5mm, and Toslink cable, and reconnecting them. If audio still isn’t working, try replacing the cables.
Some HDMI devices may provide an audio signal that the switch is not able to decode for playback. For testing, try setting the audio format on the HDMI source to PCM (or LPCM or Linear PCM). If that works, try other formats to find the best working format for your needs.