Outlook 2003 blank email body

I’ve searched high and low for a solution. Tried every one i’ve come across and nothing works consistently. I can recieve emails fine, but when sending, body is blank. Attachments go through as do the subject lines. The thing is, SOMETIMES the emails go through without a problem??? However, this only applies to users that run Outlook. All commercial email providers recieve full emails. What would cause a few emails to get through while the vast majority are blank for Outlook users? Tried plain text, rich text, HTML, applied sp2, restarted servers, and I am at wits end. Any and all suggestions are welcome and appreciated.