Why Bluetooth isn't starting

Whenever I try to start Bluetooth by clicking the Bluetooth icon from the notification bar, it keeps displaying "Turning on...". But it doesn't start. Also tried to start from the main process but it doesn't work. Checked by restarting the device, clearing the cache & data of the Bluetooth app, and using safe mode. Got the same result. Now what is the solution, or what can be the reason behind this?