I am able to authorize and connect via imap. But I am not able to deliver a message via lmtp

I am getting this error message.

passdb didn't return userdb entries, trying the next userdb

[1] dovecot-ldap.conf.ext pass_attrs = uid=user,userPassword=password,host=host,homeDirectory=userdb_home,uidNu mber=userdb_uid,gidNumber=userdb_gid user_attrs = uid=%{ldap:uidNumber},gid=%{ldap:gidNumber},home=%{ldap:homeDirectory}

[2] pass / user db's passdb { args = /etc/dovecot/dovecot-ldap.conf.ext auth_verbose = default default_fields = deny = no driver = ldap master = no mechanisms = name = override_fields = pass = no result_failure = continue result_internalfail = continue result_success = return-ok skip = never username_filter = } userdb { args = /etc/dovecot/special-userdb auth_verbose = default default_fields = driver = passwd-file name = override_fields = result_failure = continue result_internalfail = continue result_success = return-ok skip = never } userdb { args = auth_verbose = default default_fields = driver = prefetch name = override_fields = result_failure = continue result_internalfail = continue result_success = return-ok skip = never }