Traffic logging on srx branch series

Hi,

I'm trying to log all traffic information for a specific device when it access the internet on my srx branch series network but when I do a "show log traffic-log" command the log file is empty.

Here's my current config for the logs:

set system syslog file traffic-log any any
set system syslog file traffic-log match RT_FLOW_SESSION
set security policies from-zone trust to-zone untrust policy default-permit match source-address Desktop123
set security policies from-zone trust to-zone untrust policy default-permit match destination-address any
set security policies from-zone trust to-zone untrust policy default-permit match application any
set security policies from-zone trust to-zone untrust policy default-permit then permit
set security policies from-zone trust to-zone untrust policy default-permit then log session-init
set security policies from-zone trust to-zone untrust policy default-permit then log session-close

I even tried changing the source-address to any with "set security policies from-zone trust to-zone untrust policy default-permit match source-address any" but I am still unable to get any log information.

Can anyone tell me what I am doing wrong?

Thanks!