Can't send email if not in MIME format

Hi,

The fact seems strange (maybe easy to you). I upgraded from 5.0.10 to 6.5.3FP1 and now I have the following problem : email to outside the company is not sent if not in MIME format (I get a error 21:C1 in the reply mail). On the console, there is a message “CD to MIME conversion error”.

If I set the preferences of the client to send with MIME format, the messages go out without problem (except when sending messages to an alias which goes out to a redirrected email address)

I don’t know if I a clear enough. Please help me !