A person I email often changed ISP. Since that change my emails to them come back with the error 553 spam source. This happened to one other person that I sent email, their address ended in @aol.com. I use msmtp, I have set envelope_from="yes", set from="myemailaddress@xxxxxxx", set use_from=yes in my .muttrc. My wife has windows machine running mozilla thunderbird windows version and her emails go to this person ok. Is there a way to fix this ? Tom