Failed to configure docker for Applications: Unable to determine default interface

TrueNAS General
30

You need to disable STP on br0 automatically using a pre init command (settings > advanced > init/shutdown scripts) with ip link set br0 type bridge stp_state 0. See my comment here: TrueNAS 26.0.0-BETA.2 is Now Available! - #58 by Momi_V