diff --git a/modules/nixos/zulip.nix b/modules/nixos/zulip.nix
index 0240756..6f30ead 100644
--- a/modules/nixos/zulip.nix
+++ b/modules/nixos/zulip.nix
@@ -22,6 +22,7 @@
     zulipSettings = rec {
       # email settings
       ZULIP_ADMINISTRATOR = "admin@${config.networking.domain}";
+      EMAIL_HOST_USER = ZULIP_ADMINISTRATOR;
 
       # configure mailserver port
       EMAIL_HOST = config.mailserver.fqdn;