Bluetooth adapter (device) disappeared

English Hardware
#1

Hello,

My bluetooth adapter disappeared once, not sure about the exact reason. No hardware switches or keyboard switches. Now trying to work with bluetooth says that “no adapters found”. I guess it became invisible to the system.
will appreciate your help.

Regards.

#2 
sudo rfkill unblock bluetooth

HELPED.

#3

Deleted since the problem was solved while I was typing.