Why won't bluetooth turn on in Ubuntu 18.04?

Question

ubuntu

Ubuntu 18.04
In the settings I try to enable bluetooth, the checkbox shows that the bluetooth is enabled, but the same blueman does not see the bluetooth.
Yes, and in the system itself, when you go into the bluetooth settings, then there is also not a single device.
Sometimes in the top bar it is not possible to turn the bluetooth on or off at all.