Michael Schmitz <schmitz@mail.biophys.uni-duesseldorf.de> writes: > > Your mailer is rejecting valid email messages from me with no > > explanation. FIX IT. > > 550 We don't accept mail from spammers isn't enough of an > explanation? Nope. > Your ISP somehow landed itself on our blacklist. My ISP is the University of California. > I'll look into that immediately :-) Great.