"unknown password verifier"

[Adam Tauno Williams]

I'm stumped.

I've restored a mail store to a box and installed the Cyrus packages,
and copied the configuration files from a *WORKING* Cyrus server.  But
whenever I try to authenticate I get a "unknown password verifier"
message in the logs:

Oct 30 09:51:37 aleph imap[12614]: accepted connection
Oct 30 09:51:40 aleph imap[12614]: unknown password verifier
Oct 30 09:51:40 aleph imap[12614]: badlogin: [192.168.1.81] plaintext
adam SASL(-4): no mechanism available: checkpass failed


This is on OpenSuSE 10.1 using the provided packages, same as the working server.

Packages installed:
cyrus-sasl-2.1.21-18
cyrus-sasl-saslauthd-2.1.21-18.3
cyrus-imapd-2.2.12-27

Test saslauthd wors:
aleph:/home/awilliam/tmp # testsaslauthd -u adam -p *******
0: OK "Success."

aleph:/home/awilliam/tmp # grep sasl /etc/imapd.conf
sasl_pwcheck_method: saslauthd
sasl_mech_list: PLAIN
allowplaintext: 1

Any clues?  As far as I can tell configuration is identical to working
server.