[Galaxy S25] Fingerprint scanner not working?

since you ran the diagnostics per @Mujibar its highly recommended to have a service center look at it first as any hardware issues will decrease the trade in value or cause your trade in to be rejected. You don't have to make a decision at the diagnostic center right away either and they can atleast tell you whats going on with your device. They will be able to adivse whether the repair is warranty as well however that will depend on when the device was purchased. Also trading in mid cycle depending on if you are doing a carrier trade in as well as trading directly to Samsung will decrease the trade in value. I can also highly suggest investing in the top tier Samsung theft care +loss. It absolutely pays for itself. I have had to use that for a screen replacement on my s25 ultra when I accidentally broke the screen. The policy is $15 a month plus tax. The full front and back screen replacement cost me $1 when I had to use it as accidental damage is covered 😎