Comment 16 for bug 2006517

From Jesse, the interface is not connected, could you try below connect command and try your app again?

$ sudo snap connect bluez:bluetooth-control

acelankao@ubuntu:~$ sudo btmgmt version
Version 5.53
acelankao@ubuntu:~$ sudo btmgmt revision
Invalid command in menu main: revision

Use "help" for a list of available commands in a menu.
Use "menu <submenu>" if you want to enter any submenu.
Use "back" if you want to return to menu main.
acelankao@ubuntu:~$ sudo btmgmt monitor.features
Invalid command in menu main: monitor

Use "help" for a list of available commands in a menu.
Use "menu <submenu>" if you want to enter any submenu.
Use "back" if you want to return to menu main.
acelankao@ubuntu:~$ sudo btmon --mgmt
sudo: btmon: command not found
acelankao@ubuntu:~$ sudo bluez.btmon --mgmt
/snap/bluez/334/usr/bin/btmon: unrecognized option '--mgmt'