Hi Praveen,
I maintain riseup-vpn in debian. As you might see in the dependency list, it depends on
policykit as "policykit-1-gnome | polkit-1-auth-agent"
If this is not functional for you, there is nothing I can do from riseup-vpn side to make
it work. As it works for Evangelos, please kindly check if this works as well for you and ensure
that this is not a local issue.
Thank you
Nilesh