Device Bluetooth unable to pairs with Samsung Level U Headphone

[Soh]

I trying to pairs my Bluetooth headphones to my Xperia XZ but my smartphone cannot search /locate headphone Bluetooth. It always says cannot find any Bluetooth device in Bluetooth setting window. Before yesterday it was working but yesterday I reset my mobile since then having facing this annoying issue.?
Need urgent solution from any one out there.
Thanks

[Lord_viridis · Accepted solution]

It's because "before yesterday it was working"
You need to reset the level u earphones and/or put them in pairing mode or they remain locked to the registered device they are paired with