I am trying to migrate users to Zimbra, using imapsync to move mail. However I am getting an error when I attempt to use the zimbra password (We have external LDAP authenication on):

Host zimbra-proxy01.domain.com says it has NO CAPABILITY for AUTHENTICATE LOGIN
Error login: [zimbra-proxy01.domain.com] with user [john.doe] auth [LOGIN]: 2 NO LOGIN failed
Error login: [zimbra-proxy01.domain.com] with user [john.doe] auth [LOGIN]: 2 NO LOGIN failed

it is the same regardless if I use the fallback option.

Thanks,

Rick