lost my dongle bought a new one but cannot pair

Hi guys my dongle for Viper V3 Pro went disappeared so I bought a new 8k dongle from the store and did all the firmware updates and was trying it pair them according to manual through Synapse 4. However in the dongle page it just won’t detect the mouse. I made sure it’s powered on with white light flashing and not connected to the cable. Anyone can’t help with that please? Is there an unpair procedure or do I need to reset the mouse?