diff --git a/apps/mailserver/15.0.2/docker-compose.yml b/apps/mailserver/15.0.2/docker-compose.yml
index 06c565185..bab72e108 100644
--- a/apps/mailserver/15.0.2/docker-compose.yml
+++ b/apps/mailserver/15.0.2/docker-compose.yml
@@ -46,7 +46,7 @@ services:
       - SSL_CERT_PATH=/tmp/dms/certs/${CERTS_PUBLIC_CRT:-public.crt}
       - SSL_KEY_PATH=/tmp/dms/certs/${CERTS_PRIVATE_KEY:-private.key}
       - SPOOF_PROTECTION=1
-      - https_proxy=${http_proxy}
+      - HTTPS_PROXY=${HTTP_PROXY:-}
     healthcheck:
       test: "ss --listening --tcp | grep -P 'LISTEN.+:smtp' || exit 1"
       timeout: 3s