I can see .html attachment symbol in messages but when I open it there is no attachment.
I think Zimbra cannot decode base64 attachments.
Did you have experience about it ?
I read these articles:
the thread called "zimlet for decoding base64-encoded attachments" into section "Zimbra Collaboration Suite > Zimlets" , written by gray03.
what do you think ?
If it can be useful I show the original messase: