diff --git a/containers/zammad/docker-entrypoint.sh b/containers/zammad/docker-entrypoint.sh
index 9cc0c6c..2c0e850 100755
--- a/containers/zammad/docker-entrypoint.sh
+++ b/containers/zammad/docker-entrypoint.sh
@@ -121,7 +121,7 @@ if [ "$1" = 'zammad-nginx' ]; then
   check_zammad_ready
 
   # configure nginx
-  sed -e "s#listen .*#listen ${NGINX_PORT};#g" \
+  sed -e "s#\(listen\)\(.*\)80#\1\2${NGINX_PORT}#g" \
       -e "s#proxy_set_header X-Forwarded-Proto .*;#proxy_set_header X-Forwarded-Proto ${NGINX_SERVER_SCHEME};#g" \
       -e "s#server .*:3000#server ${ZAMMAD_RAILSSERVER_HOST}:${ZAMMAD_RAILSSERVER_PORT}#g" \
       -e "s#server .*:6042#server ${ZAMMAD_WEBSOCKET_HOST}:${ZAMMAD_WEBSOCKET_PORT}#g" \