fprintd-enroll works with right-index finger only

Question

When I try any other finger with:

%> fprintd-enroll left-index-finger
Using device /net/reactivated/Fprint/Device/0
failed to claim device: Not Authorized: net.reactivated.fprint.device.setusername

It doesn't work for me;

But if I don't specify finger (which uses right-index by default):

%> fprintd-enroll 
Using device /net/reactivated/Fprint/Device/0
Enrolling right index finger.

It works

Running on Arch Linux , and packages installed from aur:

fprintd 0.4.1-4
libfprint 0.4.0-3

UPDATE

%> fprintd-enroll -f left-index-finger
Using device /net/reactivated/Fprint/Device/0
Enrolling right index finger.

Answer 1

From the fprintd man page:

fprintd-enroll [username]
and
-f finger
For fprintd-enroll, the finger to enroll

It looks like you are placing "left-index-finger" as the username. and the user left-index-finger is Not Authorized