if you are using a yahoo email address to post to the lammps-users
mailing list, you should be aware, that many of your fellow
subscribers won't see them.
there is a long-standing disagreement between yahoo and other e-mail
hosting services about how signal what is a legitimate sender and
receiver of e-mails and due to some changes that yahoo did a couple
years back, many e-mails from yahoo addresses will be flagged as spam
for receivers that are not on yahoo or receive the e-mail through a
mailing list. this affects, for example most LAMMPS developers using
gmail for reading mailing list e-mails (e.g. steve, aidan and me).
there is no simple way to resolve this outside of switching to a
different e-mail service.