ChirpStack Packet Multiplexer - Does not forward

Hi,

I tried running the ChirpStack Packet Multiplexer but in all tries without success.
Tried several operating systems(Windows, Mac, Linux and within a docker container).
Build from source and apt install.

The multiplexer never emits the packets towards the backend. Image below shows the exact problem.

Config used:

log_level=4
bind="0.0.0.0:1701"

[[packet_multiplexer.backend]]
  host="0.0.0.0:1800"
  gateway_ids = [
    "6161616161616161"
  ]

#This sends the same traffic from the forwarder to TTN
[[packet_multiplexer.backend]]
  host="router.us.thethings.network:1700"
  gateway_ids = [
    "6161616161616161"
  ]

Someone got the solution? Thanks!