debug: received-header: cannot use DNS, do not trust any hosts from here on debug: received-header: relay 163.166.43.74 trusted? no debug: received-header: relay 163.166.43.74 trusted? no debug: received-header: relay 163.166.43.54 trusted? no debug: received-header: relay 161.2.239.202 trusted? no debug: received-header: relay 161.2.251.42 trusted? no
The above is likely a serious contributor to your problem. Why aren't any of the mail relays trusted?
Perhaps you should look into setting trusted_networks manually. Make sure SA trusts your mailservers.
