diff --git a/docker-compose.mail.yml b/docker-compose.mail.yml
index 750c5ac..b4d6234 100644
--- a/docker-compose.mail.yml
+++ b/docker-compose.mail.yml
@@ -42,7 +42,8 @@ services:
       - SASLAUTHD_LDAP_PASSWORD=${LDAP_BIND_PW}
       - SASLAUTHD_LDAP_SEARCH_BASE=${LDAP_SEARCH_BASE}
       - SASLAUTHD_LDAP_SERVER=${LDAP_HOST}
-      - SASLAUTHD_MECHANISMS=ldap
+      - SASLAUTHD_MECHANISMS=rimap
+      - SASLAUTHD_MECH_OPTIONS=kopano_gateway
       - SMTP_ONLY=1
       - SSL_TYPE=self-signed
       - TZ=${TZ}