[Mimedefang] Problem with HTML formated message

[Mathew Thomas]

Hi ,

We have got a sendmail +mimedefang-2.36 + spamassassin 2.55 installation on solaris 9  which is acting as our mail gateway. Mail from gateway will be sent to a GroupWise server. Some users now are complaining that they are not getting HTML formatted mail message, but some got HTML e-mail without any problem. Looks like the problem arise when the sending host do a check on whether the receiving host accept HTML formatted mail or not. These users  are getting error message something like below from the sending host:


E-mail error
The Daily Dilbert is best viewed as HTML e-mail. You have either chosen to receive a text-only version of the Daily Dilbert or your mail system does not support HTML mail. Contact your Internet Service Provider or mail system administrator to learn more about viewing HTML e-mail.

How can I fix this problem?

Thanks 
Mathew