Unknown user or password incorrect

rekan2 saya install squirrelmail dan ketika saya akses dari webmailnya pesen
error Unknown user or password incorrect. padahal user dan pasword system yg
saya masukkan kira2 kenapa yah dan kalau saya lihat di lognya seperti
dibawah ini
Apr 22 16:55:24 ns imapd: Connection, ip=[::ffff:127.0.0.1]
Apr 22 16:55:29 ns imapd: LOGIN FAILED, ip=[::ffff:127.0.0.1]
Apr 22 16:55:29 ns imapd: DISCONNECTED, ip=[::ffff:127.0.0.1], headers=0,
body=0
Apr 22 16:56:02 ns imapd: Connection, ip=[::ffff:127.0.0.1]
Apr 22 16:56:07 ns imapd: LOGIN FAILED, ip=[::ffff:127.0.0.1]
Apr 22 16:56:07 ns imapd: DISCONNECTED, ip=[::ffff:127.0.0.1], headers=0,
body=0
Apr 22 16:56:24 ns imapd: Connection, ip=[::ffff:127.0.0.1]
Apr 22 16:56:29 ns imapd: LOGIN FAILED, ip=[::ffff:127.0.0.1]
Apr 22 16:56:29 ns imapd: DISCONNECTED, ip=[::ffff:127.0.0.1], headers=0,
body=0



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Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.665 / Virus Database: 428 - Release Date: 4/21/2004