Delivery Temporarily Suspended Unknown Mail Transport Error Postfix Upd Upd Here

When you see the error delivery temporarily suspended: unknown mail transport error , it means that Postfix has attempted to deliver a message but has encountered an internal problem that prevents it from determining which transport (or how) to use. This is a , which Postfix classifies as a 4.x.x error. It will continue to retry delivery for a period (usually several days) before giving up and returning the message to the sender as undeliverable.

# Service Name Type Private Unpriv Chroot Wakeup MaxProc Command custom_filter unix - n n - - pipe flags=R user=filterargv=/usr/bin/filter-script.sh $sender $size $recipient Use code with caution. When you see the error delivery temporarily suspended: