This video shows you how to fix the following issue:
No sound when connected to PC with dongle but Bluetooth connection works with PC, Windows and Linux.
Timestamps:
00:00 Video start
00:02 Turn on the headset
00:16 Turn dongle switch from USB mode to XBOX mode
00:22 Turn dongle switch from XBOX mode to USB mode
00:32 Sound is now working again with the PC dongle
