Jammy virtual machine, installed software-properties-{common,gtk} and python3-software-properties all from proposed (0.99.22.6).
With Ubuntu Pro disabled and disconnected from Internet, clicked "Enable Ubuntu Pro".
The dialog controls were disabled and a string 'Unable to connect to Ubuntu Pro servers. Check your internet connection.' was displayed at the bottom.
I connected to Internet and the dialog went away. Controls were unlocked and a PIN was generated, with which I successfully attached the machine to Ubuntu Pro.
Jammy virtual machine, installed software- properties- {common, gtk} and python3- software- properties all from proposed (0.99.22.6).
With Ubuntu Pro disabled and disconnected from Internet, clicked "Enable Ubuntu Pro".
The dialog controls were disabled and a string 'Unable to connect to Ubuntu Pro servers. Check your internet connection.' was displayed at the bottom.
I connected to Internet and the dialog went away. Controls were unlocked and a PIN was generated, with which I successfully attached the machine to Ubuntu Pro.