diff --git a/mail-server/postfix.nix b/mail-server/postfix.nix
index 79b2eca..9b89d96 100644
--- a/mail-server/postfix.nix
+++ b/mail-server/postfix.nix
@@ -277,7 +277,7 @@ in
         recipient_delimiter = cfg.recipientDelimiter;
         smtpd_banner = "${cfg.fqdn} ESMTP NO UCE";
         disable_vrfy_command = true;
-        message_size_limit = toString cfg.messageSizeLimit;
+        message_size_limit = cfg.messageSizeLimit;
 
         # virtual mail system
         virtual_uid_maps = "static:5000";