We use P560 and Fanvil phones. Fanvil phones has feature to auto call again if number is busy, but we can't use it, becasuse we get BYE to Fanvil phone. On WAN side we get 486 busy here.
Can we set that 486 is forwarded from WAN to LAN?
Link to photo: https://ibb.co/VqyFpbS
Left side internal LAN, right side WAN