First thing to try, in the members app in the support tab, go to diagnostics, go straight to Wifi and test it. If there is failure, call Samsung support.
Next try this, go to settings, apps, where you see it say your apps, there will be 3 lines with an arrow pointing down, tap on that, turn on show system apps, type in Bluetooth, tap to open, go to storage and clear cache.
If that doesn't work, try a wipe cache partition.
If that doesn't work, go to Rest settings and Reset Wifi and Bluetooth Settings.
Yes, I got the Bose speaker to connect. I have 3 different kinds of earphones and none of the signals got pick up. Even my IPhone earphones are not showing up.
I have a Bose SoundLink speaker and I did have QC II earbuds. Coincidentally they packed up when I got my S25 ultra. Sent them back to Bose, as still under warranty, have now got the Bose Ultra Earbuds - same problem.
So it's obviously an issue with the phone, but it's only with these earbuds, all my other Bluetooth devices are fine. Done the usual reset stuff, cache, except for a factory reset which I'm trying to avoid because I have to log into my work remote with it and I will have to request another code if I do a wipe.
The Bose earbuds work fine with my iPhone as I'm listening to them now, so it's definitely an S25 ultra issue
