I think you need to provide details on your system and make sure your current pools are okay. You are also describing the pools a bit strange and not using ZFS terminology. Primary pool is RaidZ1 with two vdevs of 4 hard drives. If you lose two drives in either of the vdevs, your entire pool is gone.
Do you have a good, current backup of your pools? We can also work through the iSCSI issues but that will require some better details too. Maybe describing your network setup
https://forums.truenas.com/t/joes-rules-to-asking-for-help/12740