diff --git a/core/nginx/conf/nginx.conf b/core/nginx/conf/nginx.conf
index d1103f79..b779f98e 100644
--- a/core/nginx/conf/nginx.conf
+++ b/core/nginx/conf/nginx.conf
@@ -92,7 +92,7 @@ http {
         rewrite ^({{ WEB_WEBMAIL }})$ $1/ permanent;
         rewrite ^{{ WEB_WEBMAIL }}/(.*) /$1 break;
         include /etc/nginx/proxy.conf;
-        client_max_body_size {{ MESSAGE_SIZE_LIMIT }};
+        client_max_body_size {{ MESSAGE_SIZE_LIMIT|int + 8388608 }};
         proxy_pass http://$webmail;
       }
       {% endif %}