Dovecot proxy with ldap, complains about 'host not given'

It looks like the dovecot proxy can authenticate correctly but fails then on with this message

Nov 23 23:33:33 test2 dovecot: pop3-login: Error: proxy: host not given: user=<test>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=

I have configured a host= in ldap for this user