diff --git a/.examples/docker-compose/with-nginx-proxy/mariadb/fpm/web/nginx.conf b/.examples/docker-compose/with-nginx-proxy/mariadb/fpm/web/nginx.conf
index 8fbc162b..a1e7b03f 100644
--- a/.examples/docker-compose/with-nginx-proxy/mariadb/fpm/web/nginx.conf
+++ b/.examples/docker-compose/with-nginx-proxy/mariadb/fpm/web/nginx.conf
@@ -144,6 +144,10 @@ http {
 
             fastcgi_intercept_errors on;
             fastcgi_request_buffering off;
+
+            # Horde, used by nextcloud mail app, needs $_SERVER['SERVER_NAME'] to generate Message-ID header
+            # See also: https://github.com/nextcloud/mail/issues/5764
+            fastcgi_param SERVER_NAME $host;
         }
 
         location ~ \.(?:css|js|svg|gif)$ {