My camera flash has stopped working on apps such as snapchat and the regular camera app

Recently my camera flash has stopped working on apps such as snapchat and the regular camera app on the phone. When i go to turn it on there is an icon that when pressed says that the flash is disabled because of low battery. This has been happening when my phone is on 100% and i’m unsure why it isn’t working. Also when i use snapchat with the flash it shows the flash is on however there is no actual flash when i go to take a photo. Please can someone explain why?

[Re-Titled by Moderator]