в /var/log/warn есть такие логи:Sep 4 02:40:06 server pop3d: authentication error: Input/output error
Sep 4 02:40:44 server pop3d: authentication error: Input/output error
Sep 4 03:05:21 server pop3d: authentication error: Input/output error
Sep 4 03:10:23 server pop3d: authentication error: Input/output error
Sep 4 03:10:24 server pop3d: authentication error: Input/output error
Sep 4 03:10:25 server pop3d: authentication error: Input/output error
Sep 4 03:10:26 server pop3d: authentication error: Input/output error
Sep 4 03:10:31 server pop3d: authentication error: Input/output error
Sep 4 03:14:28 server pop3d: authdaemon: s_connect() failed: Connection refused
Sep 4 03:14:28 server pop3d: [Hint: perhaps authdaemond is not running?]
Sep 4 03:14:28 server pop3d: authentication error: Connection refused
Sep 4 03:14:29 server pop3d: authdaemon: s_connect() failed: Connection refused
Sep 4 03:14:29 server pop3d: [Hint: perhaps authdaemond is not running?]
Sep 4 03:14:29 server pop3d: authentication error: Connection refused
Sep 4 03:14:30 server pop3d: authdaemon: s_connect() failed: Connection refused
Sep 4 03:14:30 server pop3d: [Hint: perhaps authdaemond is not running?]
Sep 4 03:14:30 server pop3d: authentication error: Connection refused
Sep 4 03:14:30 server pop3d: authdaemon: s_connect() failed: Connection refused
Sep 4 03:14:30 server pop3d: [Hint: perhaps authdaemond is not running?]
Sep 4 03:14:30 server pop3d: authentication error: Connection refused
Sep 4 03:30:53 server pop3d: authentication error: Input/output error
Sep 4 03:30:56 server pop3d: authentication error: Input/output error
Sep 4 03:30:56 server pop3d: authentication error: Input/output error
Sep 4 03:35:23 server pop3d: authentication error: Input/output error
Sep 4 03:35:29 server pop3d: authentication error: Input/output error
Sep 4 03:35:30 server pop3d: authentication error: Input/output error
но это я так понимаю именно тогда, когда уже отвалился authdaemond
поэтому исходную причину не разъясняет