My Galaxy S8+ wired fast charging stopped working recently using the proper Samsung cables and chargers. It will initially say fast charging when plugged in, then 2-5 seconds later make a tone again and revert to slow charging. I believe this started with the latest security update.
VDPHB, fast charging is fantastic for a quick power up. I'm sorry you're having trouble with your fast charging. Let's work together to figure out the cause of this issue. To confirm, you're using the Adaptive Fast Charging Wall Charger that came with the device? Here's a link to that charger from Samsung's website so that you can take a look: http://spr.ly/6585DZoQc
Have you tried Fast Charging with another Fast Charger of any kind, wired or wireless? The last thing I'd like to do is run a Device Health Check for your S8+. The check will do a quick look at your phone, and let us know if there are any issues with your phone. The Health Check is on your My Verizon app, some easy to use instructions can be found here: http://spr.ly/6586DZoQY
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