The sent messages cannot be written to the INBOX.Sent mailbox (but are sent all right): "Error in IMAP command received by server."
ERROR:
ERROR : Could not append message to INBOX.Sent.
Server responded: Error in IMAP command received by server.
ERROR:
ERROR : Connection dropped by imap-server.
Query: LOGOUT

Is this because of webmail version(or an incompatibility with  server software versions?) i use ? 
It's strange because themessages are being sent through fine it's just that error that appears