Bluetooth not working

Just purchased 2 of these and they both see my sony Bluetooth headphones and connect no issues, however they see my wife’s Bluetooth headphones Yeehyc 4 in 1 Upgrade Stereo Wireless Foldable Headsets and won’t connect? Confused. Com on this!! Why would they see and connect to one set of headphones and not the other ? I see others here are having issues and do sandisk ever reply on these forums ?