Hi, I'm running a Centos 5.1 server that uses saslauthd to allow sendmail SMTP relaying for some clients. saslauthd is configured to use method "shadow" to lookup the username / password directly from /etc/shadow. This setup has been working for several month now, but is broken since last Monday. I haven't changed anything neither on the server nor on the clients. Now whenever a client tries to relay email I see this messages in the logs: /var/log/maillog: AUTH failure (LOGIN): authentication failure (-13) SASL(-13): authentication failure: checkpass failed /var/log/messages: saslauthd[3665]: do_auth : auth failure: [user=username] [service=smtp] [realm=] [mech=shadow] [reason=Unknown] Does someone have an idea how to debug this further, esp. how to find the real reason as the message [reason=Unknown] is not very helpful at all. Thanks in advance, Bernd.