i installed new version 2.0.20. but its the same problem

args = username_format=%u /etc/dovecot/users ...

Apr 21 17:47:16 host1 sendmail[32561]: q3LElF79032559: to=<jamal@example.com>, ctladdr=<root@host1.bigmama.com> (0/0), delay=00:00:00, xdelay=00:00:00, mailer=dovecot, pri=120292, relay=dovecot, dsn=4.0.0, stat=Deferred: dovecot mailer (/usr/local/libexec/dovecot/dovecot-lda) exited with EX_TEMPFAIL

Any logs for dovecot? Same sendmail configs as before or did you try the extra flag I suggested?

Joseph Tam <jtam.home@gmail.com>