My test was with RHEL 5.4 saslauthd 2.1.22-5.el5 against Courier-IMAP server 3.0.8. Apr 21 10:36:47 2010 saslauthd[23061]: auth_rimap: unexpected response to auth request: MESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS] Courier-IMAP ready. Copyright 1998-2005 Double Precision, Inc. See COPYING for distribution information. Apr 21 10:36:47 2010 saslauthd[23061]: do_auth : auth failure: [user=test] [service=smtp] [realm=] [mech=rimap] [reason=[ALERT] Unexpected response from remote authentication server] Another point: Another server with RHEL 3.4 with cyrus-sasl-2.1.15-10 is working without any error. ANy help will be appreciated. Oguz.