Error 554: which now happens tells me someone's internet provider switched to authenticated smtp message handling. Looks like openssl or sasl is going to be needed to send with that provider in the future. If there is any way possible to avoid sendmail I'd continue to do so. First, sendmail is the oldest and softest hacker exploit target on the internet after all Microsoft products. Second, how anybody gets authentication working in sendmail is something best left for those that were sending email about 2,000 years ago. Not easy at all and may involve a kernel rebuild.
