Message contains invalid header

[Marten Lehmann]

Hello,

>     case IMAP_MESSAGE_CONTAINSNULL:
>         prot_printf(pout, "554 5.6.0 Message contains NUL characters\r\n");
>         break;

especially this appears very often. Does Cyrus actually mean the whole 
message, or message body or header? What can I do with existing messages?

Regards
Marten