pluginviewer returned this, as well as several other plugins : List of server plugins follows Plugin "plain" [loaded], API version: 4 SASL mechanism: PLAIN, best SSF: 0, supports setpass: no security flags: NO_ANONYMOUS features: WANT_CLIENT_FIRST|PROXY_AUTHENTICATION
So you don't have the GSSAPI mech available. As noted, if you're using a distribution provided build of cyrus-sasl, you may have to specifically install additional mechanisms, such as GSSAPI.
--Quanah -- Quanah Gibson-Mount Platform Architect Zimbra, Inc. -------------------- Zimbra :: the leader in open source messaging and collaboration