diff --git a/test/docker_mail/templates/mailu/overrides/postfix/postfix.cf b/test/docker_mail/templates/mailu/overrides/postfix/postfix.cf
index 48b54f2e4bd8fc38df784d8b6cf08acd2915a760..7c0123e79805c85732436ebb7c34c66ec48de90c 100644
--- a/test/docker_mail/templates/mailu/overrides/postfix/postfix.cf
+++ b/test/docker_mail/templates/mailu/overrides/postfix/postfix.cf
@@ -10,5 +10,5 @@ owner_request_special = no
 unknown_local_recipient_reject_code = 550
 
 local_recipient_maps = regexp:/opt/mailman/postfix_lmtp
-transport_maps = regexp:/opt/mailman/postfix_lmtp, lmdb:/etc/postfix/transport.map, ${podop}transport
-virtual_mailbox_maps = regexp:/opt/mailman/postfix_lmtp, ${podop}mailbox
+transport_maps = regexp:/opt/mailman/postfix_lmtp, lmdb:/etc/postfix/transport.map, \${podop}transport
+virtual_mailbox_maps = regexp:/opt/mailman/postfix_lmtp, \${podop}mailbox