smtp sasl auth errors

imap auth works with courier, postfix receiving, routing mail properly,
squirrelmail receiving and sending properly (through relay on local
network), but smtp auth problems:

winstonford$ telnet 123.com 25
Trying xxx.51.132.147...
Connected to 123.com.
Escape character is '^]'.
220 123.com ESMTP Postfix
ehlo 123.com
250-123.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-AUTH PLAIN
250-AUTH=PLAIN
250 8BITMIME
auth plain dGVzdAB0ZXN0AHRlc3Q=
535 Error: authentication failed
auth plain 123
535 Error: authentication failed

Jan 19 20:13:50 meso postfix/smtpd[3152]: connect from
c-xx-99-33-22.atl.client2.attbi.com[xx.99.33.22]
Jan 19 20:14:13 meso postfix/smtpd[3152]: warning: SASL authentication
failure: Password verification failed
Jan 19 20:14:13 meso postfix/smtpd[3152]: warning:
c-xx-99-33-22.atl.client2.attbi.com[xx.99.33.22]: SASL plain
authentication failed
Jan 19 20:14:33 meso postfix/smtpd[3152]: warning: SASL authentication
failure: Can only find author (no password)
Jan 19 20:14:33 meso postfix/smtpd[3152]: warning:
c-xx-99-33-22.atl.client2.attbi.com[xx.99.33.22]: SASL plain
authentication failed

/usr/lib/sasl2/smtp.conf:

pwcheck_method: auxprop
auxprop_plugin: sql
sql_engine: mysql
mech_list: PLAIN LOGIN
sql_hostnames: localhost
sql_user: sascon
sql_passwd: sascon
sql_database: postfix
sql_select: SELECT password FROM mailbox WHERE username = '%u@%r'

user sascon does not show up in mysql log, postfix and courier do
connect successfully as user postfix.