I would try completely removing your Buds from the device and trying to pair them again. If it still can't see them, manually put the Buds into pairing mode. You can do this by placing both earbuds in the open case and press and hold the pairing button on the bottom of the case until the LED light flashes red, blue, and green. It should then show up while scanning for Bluetooth devices.
Hello ronkush, welcome to the Samsung Community! I understand your frustrations about your device not connecting to your Buds 3 via Bluetooth. Are you able to connect a different device via Bluetooth? There are a few troubleshooting steps you can try to get your Buds 3 back connected to your device:
Verify that your device and your Buds 3 are charged
Verify that your devices are up-to-date
In order to connect, most Bluetooth devices need to be within 30 feet of the phone or tablet. Make sure there are no physical obstructions or electronic devices causing interference, and place the devices close together; otherwise, they will not connect.
Samsung's earbuds and watches connect through the Galaxy Wearable app
Check if there are any restrictions or permissions that might be preventing the connection
As Llamawolfe stated, unpair and repair the Buds to your device: Open settings, tap connections, tap Bluetooth, select settings icon next to the Buds 3, tap forget device and then go through the steps to repair your device.
Reset your network settings: Open settings, tap general management and then tap reset Wi-Fi and Bluetooth settings. Next, tap Reset settings. You may be prompted to enter your security credentials.
